Question Help understanding CPU specs


Jan 9, 2017
My I5 2500k is crazy old and want an upgrade but cant figure out what signifies a faster CPU. Mine is overclocked at 4.5Ghz. I know theres far more to understanding the speed that just that though. Can anyone advise? Im planning on buying someones 2nd hand mobo / cpu that provides a decent upgrade... Just don't know what im looking for yet :/

DxDiag below:

Motherboard: Asus P8Z68-V

Operating System: Windows 10 Pro 64-bit (10.0, Build 18363) (18362.19h1_release.190318-1202)
BIOS: BIOS Date: 02/05/10 19:13:52 Ver: 08.00.10 (type: BIOS)
Processor: Intel(R) Core(TM) i5-2500K CPU @ 3.30GHz (4 CPUs), ~3.3GHz
Memory: 16384MB RAM
Available OS Memory: 16354MB RAM
Page File: 7232MB used, 25505MB available
Windows Dir: C:\WINDOWS
DirectX Version: DirectX 12
DX Setup Parameters: Not found
User DPI Setting: 96 DPI (100 percent)
System DPI Setting: 96 DPI (100 percent)
DWM DPI Scaling: Disabled
Miracast: Available, with HDCP
Microsoft Graphics Hybrid: Not Supported
DirectX Database Version: Unknown
DxDiag Version: 10.00.18362.0387 64bit Unicode

Display Devices
Card name: NVIDIA GeForce GTX 1070 Ti
There are 3 main things to look for when comparing cpu's:

1 - Core / thread count. More is generally better although for gaming there is a limit of how many cores are useful. Modern titles ideally need at least 6 threads which is why many 4 thread i5's struggle. Currently 4 core, 8 thread parts (e.g. like older i7's) have enough threads to cope with most games, there are a few very heavy titles that benefit from a 6 core / 12 thread cpus. There's not much point going for more than that if just for games.

2: Core type. This requires a little research, the type of core determines the IPC (instructions per clock) - higher IPC = faster at a given rated clock speed as it does it's work more efficiently. There are many newer CPU's that have all improved IPC since your 2500K, which is based on the Sandy Bridge core. Some notable ones are as follows:
Haswell - found in the Intel 4000 series, has a decent bump in IPC (15% ish) over the 2000 series
Skyake - another 10% faster than Haswell, the core design first released in the Intel 6000 series (also used in 7000, 8000 and 9000 series parts)
Zen / Zen+ these are the cores used in the AMD Ryzen 1000 and 2000 series, IPC is in between Haswell and Skylake
Zen 2: The newest design from AMD featured in the Ryzen 3000 series, IPC is ~10% higher than Skylake

3: Clock Speed. Higher = faster, however also need to be aware of IPC as a newer higher IPC core can often beat out an older design, even when the older design is clocked higher.

If you are looking for good second hand deals, I would suggest looking for Intel 6000 / 7000 series deals (make sure to get an i7 for the 8 threads over the i5's), or look for something based on AMD Ryzen 1000 or 2000 series (for Ryzen look out for the 6 core / 12 thread Ryzen 5 cpu's such as the Ryzen 5 1600 or Ryzen 5 2600).
The easy way to compare processors is by looking at the performance, not the underlying specs.
Passmark rating is a decent way to do this.
The passmark rating for your i5-2500K is 4089. That is when all 4 cores/threads are fully utilized.
The single thread rating is 1684.

What characteristic of a processor is most important will depend on what you want the processor to do.
For example, if you have an app that can use many threads fully, the total rating is a good comparison metric.
Some processors have hyperthreading or the amd equivalent.
This is the ability for each core to run a second thread which uses unused parts of the main thread tor added processing power. The distinction between a full core and a hyperthread is really not important. The total rating takes this into account.

Single thread performance.
Some games/apps are coded to use only a single thread. It is much simpler to code a single thread app.
Some apps simply can not be effectively broken up to be able to use multiple threads.
You find this in some games like sims, mmo, and strategy games.
Single thread performance is very important to them.
OTOH, multiplayer games with many participants are good candidates for heavy multitasking.

Single thread performance becomes more important as the number of threads that an app uses increases.
There must be a master controlling thread to manage them all.
Amdahl's law shows the decreasing effectiveness of a large number of threads.'s_law

If you are concerned about processor power usage, then the underlying manufacturing process
can be important. 7nm parts are less power hungry than 14nm.
But, the 14nm process used by intel performs about equally to the 7nm process in amd chips.

If you are looking for a cpu upgrade, the strongest processor available for your motherboard is a i7-3770K. It has 8 threads and a rating of 6408/2066
You might find one on ebay for $110.

If you want stronger, you are looking at not just a cpu upgrade, but also at a motherboard and DDR4 ram upgrade.