CPU Buyer's Guide, read this first!


Ok, since there have been a plethora of new questions, and few updates to the old guide, I thought I would write this up.

First, some terminology:

CPU - Central Processing Unit, this is the chip that makes all your components work together.

Clockspeed - The frequency at which a CPU comes rated at from the OEM.

Overclock - to increase the clockspeed by a number of methods.

Underclock - to decrease clockspeed by a number of methods.

Multiplier - The internal number that is used to determine the clockspeed of the processor

nm- nanometer: the size, at the smallest node, of the transistor nodes. Typically the largest transistor node is a few nm's larger, especially in Intel specs. 22nm in Intel technology is typically closer to ~25-26nm. Other companies typically report closer numbers.

Base Clock (BCLK) - The internal bus speed number that is multiplied by the multiplier to determine clockspeed.

Motherboard - The board into which your CPU is inserted, this has the data pathways that make communication possible.

RAM - Random Access Memory (also called memory), this is a temporary store for information your CPU will need to access while it runs a program.

Cache - This is internal memory inside a hardware component, it holds instructions waiting to be processed, or data waiting to be used.

HTT - Hyper Threading Technology, a technology employed by Intel in select CPUs that allows an idle core to run an extra thread using part of it's resources.

HTX - Hyper Transport a bus system used by AMD that allows quick data transfer (dictates the Northbridge frequency on AMD MB's).

Northbridge - One of 2 logic chips on a MB in older days, it used to facilitate communication between CPU and MB. Now many of these functions are harbored on the CPU, though not all.

Southbridge - A logic chip in the MB that integrates all of the connected devices into the MB, the SB is not directly connected to the CPU like the NB.

PCIe - PCI Express, is a protocol designed for data transfer that allows many different types of cards to be inserted into a single slot. Bandwidth is determined by the generation of the PCI Express protocol in place on the chipset.

USB - Universal Serial Bus this is a connection standard that allows thousands, perhaps even tens of thousands of different types of devices to be connected through a single port. USB is currently up to protocol version 3.0

FireWire (IEEE-1394) - The apple equivalent of USB ports, it carried over some into the PC world; however, the advent of USB 3.0 has virtually all but eliminated this format as a connection port in consumer devices. It operates in a serial format like USB, and allows "daisy chaining" of devices to link them together.

SATA (Serial ATA) - Serial Advanced Technology Attachment, this is a bus to connect mass storage devices to a PC, the bandwidth is determined by the Revision of SATA protocol available.

eSATA - External SATA, is a way to connect a SATA device to your PC via external SATA ports. It is equivalent bandwidth to SATA2 in terms of data transfer; however, because eSATA ports cannot supply power to a device, the practicality of that versus USB 3.0 (which can supply power to a device via the connection) has been all but eliminated in the modern PC market.

AGP - Advanced Graphics Port, this was in place about the same time as PCIe 1.0, and had more bandwidth then, by the time PCIe 2.0 came out, bandwidth was similar so AGP went the way of the dodo. The last usage of anything with AGP was circa 2006 to my knowledge.

AM3/AM3+ - A socket type used by AMD. AM3+ motherboards are compatible with AM3 CPUs, however, AM3 MBs are not typically compatible with AM3+ CPUs.

FM2/FM2+ - A socket type used by AMD for APUs specifically, this chipset allows the onboard graphics to function through the MB. FM2 APUs are compatible with FM2+ boards; however, once again, FM2+ APUs are not compatible with FM2 boards.

LGA 1150 - A socket used by Intel for 4th Gen Core I series CPUs.

LGA 1155 - A socket used by Intel for 2nd and 3rd Gen Core I series CPUs.

LGA 2011 - A socket used by Intel for 2nd and 3rd Gen Core I Extreme series CPUs.

"K series" - In Intel terms, these processors support unlocked multipliers when paired with a board that can use those features. In short, they're overclockable. In the APU line from AMD, they, coincidentally, also use a "K" nomenclature to denote overclockable SKUs.

Chipset - This is the terminology for the feature set offered on the MB. AMD's current Chipsets for CPUs are 970/990 and for APUs is A55/A75/A85 in FM2, and A88/A78/A58 in FM2+. Intel's current Chipsets for LGA 1150 are Z87/H87/B85/H81

GPU/iGPU: Graphics Processing Unit/integrated Graphics Processing Unit. These allow video display to function and handle graphics processing among other tasks.

GB - Gigabyte, a unit of size in PC terms, this unit is equal to 1024 MegaBytes.

DDR3 - Double Data Rate type 3 RAM, this is the type of RAM all current and last generation systems require to use. They come in DIMM format (Dual Inline Memory Module).

Dual Channel Memory - Means you benefit from having 2 sticks of RAM in the motherboard to gain more bandwidth. (4 RAM slots on the MB)

Triple Channel Memory - Means you benefit from having 3 sticks of RAM in the motherboard to gain more RAM bandwidth (6 RAM slots on the MB)

Quad Channel Memory - Means you benefit from having 4 sticks of RAM in the motherboard to gain more bandwidth (8 RAM slots on the MB)

Bulldozer - 1st Generation AMD FX series

Piledriver - 2nd Generation AMD FX series, and Trinity/Richland APUs

Steamroller - 3rd Generation AMD FX series, and Kaveri APUs

Excavator - 4th Generation AMD FX series, and Carrizo APUs

TDP - Thermal Design Power, a rough estimate of average heat dissipation due to power consumption of the chip.

Turbo Core - A system where a single core (or multiple cores) can scale up in clockspeed under light load, this is automatic and requires no user input

Binning - A term that references the quality of silicon in the chip

Nehalem - 1st Generation Core I series, socket LGA 1356.

Sandy Bridge - 2nd Generation Core I series, socket LGA 1155.

Ivy Bridge - 3rd Generation Core I series, socket LGA 1155.

Haswell - 4th Generation Core I series, socket LGA 1150.

Thuban - Phenom II series 45nm parts (K10 architecture), socket AM3

Deneb - Phenom II series 32nm parts (K10 architecture), socket AM3

Zambezi - 1st Generation FX, Bulldozer 32nm parts, socket AM3+

Vishera - 2nd Generation FX, Piledriver 32nm parts, socket AM3+

Llano - 1st Generation APU on K10 architecture, socket FM1

Trinity - 2nd Generation APU on Piledriver architecture, socket FM2

Richland - 3rd Generation APU on Piledriver architecture, socket FM2

Kaveri - 4th Generation APU on Steamroller architecture, socket FM2+

Now onto the nitty gritty bits about CPUs:

AMD Architectures:

AMD APUs: These are the AMD central processors that offer built in graphics. Essentially you don't have to buy a GPU, though you may choose to do so anyway. For a budget, an APU makes a good HTPC for small form factors, and can be a good gaming machine for light gaming. APUs require more RAM, and more RAM bandwidth to run at maximum potential. This is because they use your System RAM in the same manner a GPU would use it's VRAM on the card, in addition to your system using the RAM. I recommend no less than 8 GB (2x4 GB) of RAM and no less than DDR3-1866 MHz RAM. This is to facilitate the best possible performance from the iGPU on board the APUs.

Current APUs are in 2 generations, called Trinity and Richland. They are based on the same Piledriver cores from AMD. They come in 2 or 4 cores and all have built in iGPUs. The higher end models are denoted by A8/A10 and a series of numbers after them (A10-5800k for example).

Trinity models are slightly older than Richland, and consumer slightly more power despite similar TDP. This is primarily because Richland models have better low power states that allow less idle power consumption and slightly less peak power consumption. All A10, and A8 models are quad cores models in the desktop APU line. Those that have a number ending with a "k" are unlocked multiplier models that can be overclocked.

AMD CPUs: FX Series, Phenom II series. These are AMD's dedicated CPUs with no iGPU. They are typically quite a bit more powerful than their APU brothers because of more cores and more cache, otherwise the cores are essentially the same. Many of these models are the same basic chip, some are binned higher than others. For example: the FX 6300 and FX 6350 are exactly the same, except the 6300 operates at 95W TDP because it is clocked lower (3.5 GHz) versus the FX 6350 which operates at 125W TDP because it is clocked higher (3.9 GHz). The situation is the same between the FX 8320/8350/9370/9590 series, except the 8320 and 8350 are 125W TDP parts and the 9370 and 9590 are 220W TDP parts.

AMD chipsets:

970 series chipsets (AM3+): The 970 series typically support crossfire, though they typically have less bandwidth than the 990 series chipset boards. They typically have fewer VRMs for overclocking as well; though there are a few exceptions to this (the Gigabyte 970A-UD3 is one such example). Some boards also support SLI configurations in the 970 series chipsets; however, they are the exception. These boards typically support PCIe 2.0 x16/x1/x1/x1 or similar configurations, like PCIe 2.0 x4/x4/x4/x4 or PCIe 2.0 x8/x1/x8/x1. They also have USB 3.0 support, and SATA3 support, typically with more ports than Intel motherboards up to Z87 (Z87 boards typically match the number of ports you can get on AMD chipsets).

990 series chipsets (AM3+): This is the high end AMD chipset, it also supports USB 3.0, SATA3, and PCIe 2.0; however, there are some boards that support PCIe 3.0, like the Asus Sabertooth Gen3 R2.0 for example. This series of boards typically have more VRMs, or higher quality VRMs, or a combination of both. They are typically better for overclocking, and provide a great deal more bandwidth for PCIe 2.0. Most 990 chipset motherboards support a configuration of PCIe 2.0 x16/x4/x16/x4 or similar. That means you can crossfire or SLI 2 card at full PCIe 2.0 bandwidth levels. All 990 series chipset motherboards support both crossfire and SLI.

FX Series: When looking at the FX series, the second digit denotes the generation. A 1 is for Bulldozer, a 2 is for bulldozer second core stepping, and a 3 is for Piledriver. You want to get a processor with a 3 for the second digit, as Piledriver is about 15% more effective than Bulldozer across the board.

FX 4XXX: These FX series processors have 4 integer cores, and 2 floating point units. They are an entry level processor with performance typically falling around the i3 level give or take. They are good for light gaming; however, more demanding games will max out the CPU. These CPUs can run 4 threads at once.

FX 6XXX: These processors have 6 integer cores, and 3 floating point units. They are a mid range model priced at a very good value. One might argue that the FX 6300 has the highest price/performance ratio of any CPU currently available. Their performance will typically rival entry level locked i5 CPUs when overclocked sufficiently. These CPUs can run 6 threads at once, and they typically perform well in heavily threaded tasks. In terms of gaming, they will perform on par with the FX 8XXX series for the most part. Only in extremely heavily threaded games will you see better performance from the 8 core FX models (Crysis 3, and BF4 are the only current examples that come to mind).

FX 8XXX: These CPUs have 8 integer cores, and 4 floating point units. They are a high end model for AMD and are priced competitively with the higher end i5 series (typically a bit cheaper). These CPUs can run 8 threads at once, and are typically very good for processor heavy workloads that are well threaded (examples would be: encoding, rendering, compiling, etc.). They also offer up excellent performance in gaming, especially situations where the game is very well threaded, such as Crysis 3, BF3 multiplayer, and BF4.

A series: The A10 and A8 series are all that I am discussing here, the lower end models are not relevant for a gaming CPU. The A10/A8 series are basically the FX 4XXX series without L3 cache on the processor; instead, they have an iGPU that allows you to run some games without having to buy a discrete GPU. Keep in mind, the more demanding titles will not run well above a resolution like 720p, and typically at low/medium settings (games like Crysis 3 will not run at playable frames on the A10 series).

Athlon II X4 7XX series: This series is basically the A10/A8 models without the iGPU. They can be had for very good values in terms of price/performance versus the A series; however, without L3 cache on the CPU, they will not perform quite as well as the FX 4XXX series, and benchmarks reflect this.

Intel architectures:

Socket LGA 1156: The only architecture on this socket was the Nehalem architecture. Finding components for this series may be difficult, as new parts are not very common.

Socket LGA 1155: This socket supports the 2nd and 3rd Generation Core I series (Sandy Bridge and Ivy Bridge). These components can still be found new, though more rare than they were in the past. They typically support a few SATA3 ports, USB 2.0 in older boards, USB 3.0 has some support in the newest boards. The last iteration, the Z77 chipsets, all support PCIe 3.0. Though, at this time the advantages of PCIe 3.0 over 2.0 are virtually non-existent, at some point it will be relevant (though current GPUs cannot yet fully saturate a PCIe 2.0 x16 bus).

Z series chipset (Z75/Z77): The Z series chipset is for unlocked K series processors, and allows overclocking. The Z series chipsets all support PCIe 3.0 x16 or PCIe 3.0 x8/x8, they also come with 2 SATA3 ports and 4 SATA2 ports and 4 USB 3.0 ports. The Z series Chipsets also support RAID.

H series chipset (H77): The H77 chipset contains all of the Z series features except: 1.) They do not support overclocking, and 2.) The PCIe slots are only 1x PCIe 3.0 x16, and 1x PCIe 2.0 x8.

B series chipset (B75): The B75 chipset contains the same features as the H77 chipset with the following exceptions: 1.) B75 does not support RAID, and 2.) Intel Rapid Storage and Smart Response are not supported features.

Socket LGA 1150: This is for the 4th Gen Core I series only. The chipsets for these boards will be Z87/H87/B85, and will offer greater SATA3 port numbers, USB 3.0 support, and PCIe 3.0. As with the LGA 1155 chipsets, the Z series chipsets offer full overclocking support. In this generation, however, the H and B series boards will have some overclocking support, though the feature sets for those will likely be more limited than what is available for overclocking on the Z series chipsets.

Z87 chipset: Z87 supports Intel Clear Video, has 8 USB 2.0 and 6 USB 3.0 ports, 6 SATA3 ports, and carries over the PCIe 3.0 configuration from the Z77 chipset.

H87 chipset: H87 supports all the same features as the Z87 chipset except: 1.) RAM cannot be overclocked, 2.) The H87 chipset also supports all the virtualization features (VT-d, vPro, Active Management, and Trusted Execution, which are not supported on Z87)

B85 chipset: Supports the same features as H87 except: 1.) Does not support virtualization features, 2.) Does not support IRST and SRT, 3.) has 2 SATA2 and 4 SATA3 ports instead of 4 SATA2 and 6 SATA3.

H81 chipset: H81 is identical to B85, but does not support Clear Video technology, and only has 2 SATA3 ports.

Socket LGA 2011: This is the chipset for the Extreme series Intel processors since Sandy Bridge E. The chipset is only X79, and it offers 40 lanes of PCIe 2.0 bandwidth, which is comparable to the 990 series chipsets in the AMD boards. Additionally, some boards will likely support USB 3.0, and most should support SATA3. You will get Quad Channel Memory with the Extreme series, and have some advanced features above and beyond other chipsets that Intel offers...though this comes for a pretty hefty price tag.

Nehalem: 1st Generation Core I series, only series on socket LGA 1356. These CPUs are still serviceable for modern gaming with a good overclock; though they do tend to run hot. If you possess one and are considering an upgrade, you would achieve about a 20-25% performance increase, clock for clock to go to 4th Gen architecture. Intel architecture has not dramatically changed since Nehalem, only process tweaks have made adjustments to the core architecture.

Sandy Bridge: 2nd Generation Core I series, on socket LGA 1155. This was the last large improvement in Intel's Core I series, it was roughly a 15% gain over Nehalem. Sandy Bridge is still very relevant as a gaming platform and will be fine with an overclock for the newest games.

Ivy Bridge: 3rd Generation Core I series, on socket LGA 1155. This step to 22nm marked the beginning of Intel's push toward mobile and lower power envelopes. Because of this, the improvements from SB to IB were only about 5-8% increases across the board. IB consumes less power in desktop than any other Intel architecture under load.

Haswell: 4th Generation Core I series, on socket LGA 1150. This was a process refinement over IB at the same node. It was a greater push toward mobile focusing almost entirely on the mobile segment. Because of this, the increase from IB to Haswell is only roughly 3-5% across the board. In addition, because Intel added Ultra Low Power states to Haswell, the idle power consumption is lowest of all the Core I series; however, because of changes to the power management system of the chip, it actually consumes more power and runs significantly hotter than Ivy Bridge. This is evidenced by higher counterpart TDP, for example the TDP on the i5-3570k in Ivy Bridge is 77W, where as the TDP of the i5-4670k in Haswell is 84W.

Core i3: These are Intel CPUs that feature 2 cores with HTT. The i3 models have all been locked since the Sandy Bridge architecture. You can overclock them very moderately using BCLK, however, the effort expended is often not worth the time for the marginal performance gains it affords (max is on the order of a 300-400 MHz increase).

Core i5: These are Intel CPUs that feature 4 cores and no HTT. The i5 models are all locked like the i3 series, except for the "K series" parts like the i5-3570k or i5-4670k. The i5 models are typically substantially more powerful than the i3 series, and often trade blows with the FX 83XX series in gaming and other tasks.

Core i7: These are Intel CPUs that feature 4 or more cores, depending on the model discussed, and HTT. This range encompasses the Extreme series, as well as some other parts. Any i7 chip without a "k" after the numbers (like the i7-3770k for example) has a locked multiplier, and could only be overclocked via BCLK. Again, this is usually not worth it for the effort spent, however, it can be done on any locked Intel CPU up to Haswell. In the 4th Generation processors "Haswell" they disallowed this feature.

The strength of Intel chips lies in the fact that they have 3 ALUs per core, versus 2 per core for AMD. AMD CPUs typically have more cores, and can work better in heavily multithreaded scenarios, but lose in applications like iTunes that lean heavily on single core performance.

To get a rough approximation of value this is roughly how things break down between the FX and Core I series:

i3 ~ FX 43XX
i5 ~ FX 63XX
i5k ~ FX 83XX
i7 ~ FX 83XX

Since the majority of people here ask questions regarding gaming, let me break this down in terms of gaming performance.

I do not recommend an i3 for playing the newest games like Crysis 3 or BF3 or BF4 multiplayer. Those games generate too many threads for an i3 to be worth a consideration in such builds. By the same token, the FX 43XX series is typically overwhelmed by such things, as are the APUs.

For modern gaming you need a quad core or more processor, to that end:

The FX 63XX series performs on par with lower end, locked i5s, especially since you can overclock the FX 63XX series, and not the i5 CPUs. The FX 63XX series is a definitive notch above the i3 series and the FX 43XX series and APUs.

The i5 k series parts are about equal to the FX 83XX series in games. In some cases Intel will win a set of benchmarks, under other cases the FX series wins. You cannot go wrong with either choice when it comes to these 2.

The i7 series parts are also about equal to the FX 83XX series in games, though the FX 83XX series and the i7 class are both quite a bit better at multitasking and heavy threaded applications than the i5 series are, even the k parts.

Comparison of 8350 and 3770k:


8350 and 3570k:


9590 and 4770k:


The i7 k series parts are typically slightly above the FX 83XX series in multi threaded performance. This is especially true of the 3930k and the X series i7's that have 6 cores. Though, once you get into the i7's especially k and x series parts, you're talking ~$350 for the CPU alone typically, so be aware of that. Additionally, the performance gains in CPUs once you pass ~$200-250 begin to get smaller and smaller and cost disproportionately more money for very small performance gains. The FX 9XXX series will compete with some of these parts because of factory overclocking; however, they are simply the FX 8350 overclocked by AMD at the factory. So, unless you have no intention of overclocking and just want the added performance, I would ward you off the FX 9XXX series and point you to the FX 8350.

For all intents and purposes, most people wouldn't have need for more than something like the i7-3770k or 4770k, or the FX 8350. The sweet spot is typically somewhere around the FX 8320/8350 in AMD parts, and the i5-4670k is enough for current games that are out now. Though that may be subject to change later as some games, like Watch Dogs from Ubisoft, are recommending the i7 and 8 core AMDs as the recommended CPUs and quad core Intel processors and six core AMD processors are listed as minimum.

A rough hierarchy chart to show what CPUs are roughly equivalent:

Top Tier: (Should run anything on Ultra with a proper GPU, and will not bottleneck any GPU card out there)

AMD: FX 9590/9370/8350/8320

Intel: i5 3570k, i5-4670k, i7-3770k, i7-4770k, ALL LGA2011 CPUs (i7-3820/3930k/3960x/3970x/4820k/4930k/4960x), i7-2600k*, i7-2700k*, i5-2500k*
(*denotes will perform top tier when overclocked sufficiently)

Second Tier: (Should be fine now, and for a bit to come, but some are here because they cannot be overclocked for performance gains down the road as games become more demanding)

AMD: FX 6300/6350, FX 8120/8150,

Intel: ALL locked i5's from Sandy Bridge or newer, 1st Gen Core i7 series also fall into this tier, especially when overclocked.

Third Tier: (May struggle in games that are CPU demanding, and may bottleneck some GPUs)

AMD: FX 4XXX, FX 6100/6200, A10/A8 APUs, ALL Phenom II X4/X6 CPUs, FM2 model Athlon II X4 CPUs like the 740k/750k/760k,

Intel: ALL i3 series, 1st Gen Core i5's and Core 2 Quads.

I should note, this list is not entirely comprehensive of all possible CPUs, and all possible combinations. This is merely a guide put into layman's terms to help you determine what will best fit your needs. For specific questions about specific applications, please feel free to ask in the forums. However, this list should be able to give many of you at least an idea of what you should be looking at. Any suggestions for other things to be included are welcome.

For your own research:

I recommend everyone look at their uses of a CPU, and determine what is the best fit for their own needs. Take synthetic benchmarks with a grain of salt as well, as your system configuration may yield entirely different results.

These are the sites I recommend for your own research:







Hopefully this will get you started on the right path!

Value recommendations:

Sub $100:The Phenom II X4 or X6 is a great value here if you can still find one, and the 760k for FM2/FM2+ boards is basically the A10-6800k without the iGPU. Both of those will work for you if you're on a very tight budget. Also the A10-5700 can be had for just under $100, which gets you a higher end (locked multiplier) APU with iGPU.

$100-120: FX 6300 in AM3+ boards, and A10-5800k/A10-6800k for FM2/FM2+. The FX 6300 can be overclocked to 4.5 GHz and beyond with the right setup, and will match any locked i5 CPU from Intel at such clockspeeds. Honorable mention here goes to FX 4300/4350, and Intel i3-4330, as they would be fine for older or less demanding (or browser based) games and low resolutions like 720p or 900p.

$150-180: FX 8320/8350 in AMD is an extremely solid buy for the money. The 8320 has a higher price/performance ratio if you intend to overclock, though. If you overclock the 8320 on a 990 series board, you can typically achieve clockspeeds in excess of 4.4 GHz. With the 8350, you may achieve higher, though you pay a $30 premium for higher binning. The entry level Intel i5 processors get an honorable mention here, even though they mostly fall around the $180-$200 mark (i5-3350p/3470, and i5-4430/4570), as they will perform on par with the FX series at stock (even better in some cases); however, when you overclock the FX series, you can get performance exceeding the locked i5 processors.

$200+: There are really only 3 pairs of processors that I consider to be worth discussing over $200: The first pair is the 3570k or 4670k in the i5 line. If you want to buy Intel, this is going to be the best price/performance ratio on their unlocked k series. These can typically be found around $220-250 depending on where you live and shop.

$300+: The next pair is the i7-3770k and 4770k. If you need heavy multithread performance in a CPU, and you want more than the FX series offers at your specific tasks, these 2 processors will set you back about $310-350 on average. They will offer more performance in certain workloads than the FX 8350, though the performance gains over the FX 8 cores is typically in the range of 8-15% depending on the workload. I am also going to sneak the i7-4820k in here, as it is now unlocked access to the X79 series LGA 2011 chipsets for the extreme series.

$500+: The last pair is the i7-3930k and 4930k, these are the unlocked 6 core Extreme series CPUs with HTT, and they are extremely pricey. However, if you have to have every last drop of performance, or price isn't an issue, then this is the most performance you can get. A CPU + MB combination for one of these will typically cost you in the neighborhood of $750-800.


Aug 21, 2013
Good information, even for those of us that already know most of it. I have a bad habit of referring to my CPU as a chipset even though I know that's technically incorrect.