How to Buy the Right CPU

[mattsafford]

Whether you’re building or upgrading a new PC, the CPU matters a lot (and the chip you choose will also dictate your motherboard purchase). Here is a guide.


How to Buy the Right CPU : Read more

 

[abryant]

Archived comments are found here: http://www.tomshardware.com/forum/id-3716216/buy-cpu.html

 

[InvalidError]

Intel, on the other hand, has a tendency in recent years not to support backward compatibility with its new chips and older motherboards, even if the socket is effectively the same.

Recent years? The 8086 used a different package from the 80286 which had a different package from the 80386, which itself used a different package form the 80486, Pentium, Pentium Pro, Pentium II, Pentium III, P4, etc. Intel's history of requiring new motherboards roughly every other year goes back pretty much all the way to its first consumer processor.

The only thing new "in recent year" is the questionable justifications for forcing people to get new boards since there is nothing new IO-wise to justify it.

 

[techgeek]

In your chart of Compatible Chipsets, you missed Z390 for LGA1151v2 sockets.

 

[KenZen2B]

When do you foresee PCIe 4 and PCIe 5 in motherboards ?

How will the new standards affect gamers or are the new standards for production workloads ?

 

[InvalidError]

When do you foresee PCIe 4 and PCIe 5 in motherboards ?

How will the new standards affect gamers or are the new standards for production workloads ?

For AMD, PCIe 4.0 is going to be this summer with Zen 2. For most workloads though, it won't make any difference since there are almost no PCIe 4.0 devices out there, GPUs still don't come close to maxing out 3.0x16 or 4.0x8 yet and the benefits of NVMe over SATA 6G are borderline negligible for most uses, which means even smaller gains from going from 3.0x4 to 4.0x4 or 5.0x4.

PCIe 4.0/5.0 will have the greatest impact in large servers with massive IO requirements that cannot be met with PCIe 3.0x88 for Intel's Xeon 2S or 3.0x128 for EPYC 2S.

 

[harly2]

Ryzen, just end it their and look again in 2021 when Intel has something interesting.

 

[alexander.w.jacob]

In the list of compatible chipsets for the LGA 1151 Z370 is listed twice. I guess one of them should be changed to Z370.

 

[mitch074]

Recent years? The 8086 used a different package from the 80286 which had a different package from the 80386, which itself used a different package form the 80486, Pentium, Pentium Pro, Pentium II, Pentium III, P4, etc. Intel's history of requiring new motherboards roughly every other year goes back pretty much all the way to its first consumer processor.

The only thing new "in recent year" is the questionable justifications for forcing people to get new boards since there is nothing new IO-wise to justify it.

At least for these older chips, the fact that the 286 had a different RAM addressing scheme did justify a different pinout - same for the 386DX. But at least, for a time, Intel did provide "Overdrive" processors that allowed someone to plug a 486 in a 386DX system (both CPUs had the same bus width and memory addressing capabilities), or a Pentium in a 486 system (but it was a failure due to the bus being cut in half).

Let's not mention the days of the Socket 5/7 where a single socket could manage any chip from an original Pentium 75 to a Pentium MMX 233 and also an AMD K6-133 to the K6-3 600 and even Cyrix 6x86 chips... Now THAT was compatibility! But then Intel decided to copyright a CPU's pinout design.

Let's be honest : Intel didn't want to spend any money into making sure the 1151 design was durable; they reserved a bunch of pins and called it a day, and then only added stuff when needed. If that foced people to buy new motherboards (with an Intel chipset on it), that's only that much cash they get, since they make their own chipset.

AMD has a different profile : they don't make their own chipsets. As such, they drew up a single socket layout and paid a company (ASmedia) to design a chipset that would work for all that time. And then, they cooked as much back and forward compatibility stuff as they could in the CPU itself

 

[mspencerl87]

How to buy it??
Just buy it!

 

[g-unit1111]

I'm really surprised that the R5-2600 didn't get the Best Value award. It's a 2nd gen hex core Ryzen and it can be had for about $149 which is $50 less than the Intel i5-8400. I just bought one a few weeks ago and it's been a really great buy so far.I bought it with an Asus ROG B450 at Micro Center and for the entire thing I paid $299.You can't beat that.

 

[knowom]

I agree on R5-2600 is compelling at it's price range the tweaked Zen+ version that has the improved precision boost is a well rounded chip that is easy to recommend in almost any case over what Intel offers in a similar price bracket range. Unless you really only play at 1080p exclusively it's hard to recommend Intel.

On a side note I'm curious the impact DLSS plays at 1080p/1440p and CPU purchasing decisions. Does the initial rendering resolution of it play into the whole lower resolution lower higher CPU IPC/clock frequency dependence or does the upscale neutralize it?

Does that part simply happen on the GPU end and thus alleviate CPU bottleneck performance in certain instances? It's a DLSS question that I'd be interested in knowing more about.

 

[InvalidError]

I'm really surprised that the R5-2600 didn't get the Best Value award.

I wouldn't be too surprised if the answer ultimately boiled down to two words: affiliate links. Between two similar-enough-class products, more expensive recommendations likely translate into bigger commissions.

 

[g-unit1111]

I agree on R5-2600 is compelling at it's price range the tweaked Zen+ version that has the improved precision boost is a well rounded chip that is easy to recommend in almost any case over what Intel offers in a similar price bracket range. Unless you really only play at 1080p exclusively it's hard to recommend Intel.

On a side note I'm curious the impact DLSS plays at 1080p/1440p and CPU purchasing decisions. Does the initial rendering resolution of it play into the whole lower resolution lower higher CPU IPC/clock frequency dependence or does the upscale neutralize it?

Does that part simply happen on the GPU end and thus alleviate CPU bottleneck performance in certain instances? It's a DLSS question that I'd be interested in knowing more about.

I'm not entirely sure, but I think that would be entirely dependent on the GPU and monitor end and not the CPU end.

 

[Robert_388]

Answer: Wait for Ryzen2

If you can't wait, get a current of past Ryzen and then upgrade to the new chips later without a penalty since AM4 is backwards compatible.

 

[g-unit1111]

Answer: Wait for Ryzen2

If you can't wait, get a current of past Ryzen and then upgrade to the new chips later without a penalty since AM4 is backwards compatible.

You mean Ryzen 3? Ryzen 2 is the current generation.

And yes AM4 is backwards and forwards compatible but you have to have a current gen CPU in order to upgrade to the next one.

 

[abrogard]

why so hard to find socket type when looking at board/chipset specs?
I have an H170 and wanted to see what socket it has so googled the chipset and the board and found lots of specs without any mention!

This is a good page. But how about a one-click download of it to pdf or somesuch?

 

[InvalidError]

If you can't wait, get a current of past Ryzen and then upgrade to the new chips later without a penalty since AM4 is backwards compatible.

There is a penalty for putting a Zen 2 CPU on a Zen/Zen+ motherboard: you get no or only partial PCIe 4.0 support for the CPU's PCIe lanes.

 

[TEAMSWITCHER]

"Ryzen, just end it their and look again in 2021 when Intel has something interesting."

Huh? 9900K features near HEDT performance closer to Ryzen pricing. Availability is great with motherboard bundles offering a $30 discount from some vendors. Comparing the total system costs, spending another 7% for top-of-the chart performance is the smart choice.

 

[smalltown2]

Great article Matt.
I will help me on my next system build.

 

[smalltown2]

Wish I could edit spelling after posting. Ugh !

 

[Sam Hain]

I'd apply this article's precepts, come later in the year when newer CPU's hit the shelves...

 

[Zhyr]

What isn't taken into consideration is the number of games which are becoming CPU intensive such as any EA game on Frostbite.

There's been a huge jump in multithreaded games over the past 12-18 months.

 

[mitch074]

There is a penalty for putting a Zen 2 CPU on a Zen/Zen+ motherboard: you get no or only partial PCIe 4.0 support for the CPU's PCIe lanes.

There is indeed a penalty, but it looks like it'll be rather low: many motherboard vendors have announced that they'll provide PCIe 4.0 compatibility on some of their motherboards via BIOS updates - looks like it's a matter of PCI signal strength, as such most boards that have a single PCIe x16 slot should be able to get it, as far back as first-gen B350 boards - depending on the board's maker willing to implement it in BIOS or not (we might get a few beta BIOSes there).

Actually, the biggest letdown one may get with a first-gen AM4 board is with the B350 chipŝet not supporting 25MHz steps in power delivery; people who paid for a good X370 board in mid-2017 may actually get PCIe 4.0 and fine power management through BIOS updates on 16-core Zen2 7nm chips in 2020... Yes, it depends on the board's maker supporting their products for a while, but that's a stark contrast with Intel actually soft-locking their firmwares AGAINST it in the first place.

 

[akamateau]

Intel, on the other hand, has a tendency in recent years not to support backward compatibility with its new chips and older motherboards, even if the socket is effectively the same.

Recent years? The 8086 used a different package from the 80286 which had a different package from the 80386, which itself used a different package form the 80486, Pentium, Pentium Pro, Pentium II, Pentium III, P4, etc. Intel's history of requiring new motherboards roughly every other year goes back pretty much all the way to its first consumer processor.

The only thing new "in recent year" is the questionable justifications for forcing people to get new boards since there is nothing new IO-wise to justify it.

Intel does support backward compatibility with vulnerabilities to malicious attack.
Intel cpu's simply are not secure.
Intel sacrificed security in order to gain an edge in single core performance.