Upgrading an Intel Core i5 2500K machine's CPU. Am I going to pull my hair out?


My son is looking to upgrade his PC (how I look in envy at his fancy 5+ year old tech while typing on my i7-920 based PC :) ). He is convinced that this CPU has become the choke point for his gaming.

He’s updated his RAM and video card over the past few years (pretty sure he is rocking a NVidia 1070 right now). But the core components of the machine haven’t changed since he got it:

  • CPU: Intel Core i5 2500K 3.30GHz @ 4.40GHz Sandybridge CPU
  • Motherboard: Intel Z68 (Socket 1155) DDR3 Motherboard ** B3 REVISION **
  • Power Supply: OCZ ZS 650w PSU

Looking at various sites, I was surprised to see that his motherboard might actually support all the way to the current i7 -3xxx CPU’s. Back in my day, Intel would obsolete your chipset faster than you could upgrade it… Is that really the case? Any pitfalls I should be aware when selecting the next CPU line? Any limitations inherent to the chipset?

Since the motherboard still seems to support very decent CPU’s, I’m not looking at taking the whole machine apart and swapping to Ryzen or anything that traumatic.

And speaking of chipset and motherboard, this is a standard Intel motherboard with, as far as I remember, standard cooling (big heatsink on the CPU, …). I’ll have him bring his PC over next time he comes around to doublecheck.

How hard is it to swap CPU’s these days? I haven’t manually upgraded a CPU since the Pentium days. So I’m a tad out of touch. Am I likely to destroy the machine in the process?

Any recommendations or word of advice would be much appreciated!


If he’s running it steady at 4.4 right now he’s not going to get much of an improvement at all unless he goes all the way to Haswell or better at a similar overclocked frequency (the 4xxx line). Going from 2500k to 3xxx isn’t going to get you much.

Also old CPUs don’t really drop in price much. You’re better off buying just one generation back from the hottest, like a 6700K, with a new motherboard. Although I guess you’re RAM might be older?

Is it because of costs you’re really wanting to keep that motherboard rather than just do new guts all around? I have an i5-3570k, and I’ve just started hitting some limitations with it. You’re going a half-step up but still going to an old chipset.

My PC is basically your son’s PC, and I’m contemplating a replacement sooner than later. That said, upgrading the CPU isn’t in the plans - for the cost, I’m planning on grabbing a more modern semi-barebones PC and then carry over my GPU, PSU, and HDD.

He’d probably be right - the better the GPU, the more the CPU becomes the limiting factor in maintaining solid high framerates. The 3xxx was only 1 year after the 2xxx so it’s not surprising the motherboard would still support it.

I think he’ll still be CPU bound using an i7-3xxx, I upgraded from my i5-4xxx for the same reason (MB, CPU, RAM). Mind you, it does depend on what res/framerates/detail settings you’re after.

Yeah what @quaro said!

Thanks @Quaro, @Nesrie, @Dan_Theman, @Profanicus and @wumpus. What you say makes a lot of sense. I was having a brainfart moment where I throught the i7-3xxx were more recent than they are. They would indeed be a pretty poor value for money upgrade all things considered.

That said, my 19 year old son is indeed a poor student and his budget limited. I’m really wary of having to take everything apart to fit in a new motherboard and then plug everything back in, then deal with Windows throwing a fit because all its low level drivers are wrong.

I also wonder like @Dan_Theman whether the more sensible route might not be to go for a barebones config with a crap video card, possibly not much memory (though I need to check on the frequency of my son’s 12GB of DDR3 RAM) but in a modern case. Then fit back in his hard disk, GPU, RAM, … Then I only have to deal with Windows and not rebuild the whole machine.

That means I get his case, motherboard and CPU as a barebones upgrade to my 2009 CPU too. How far I’ve fallen from the bleeding edge.


Upgrading the CPU/mobo/RAM will cost around $430. Yes, you’ll need DDR4 for Skylake/Kaby and Ryzen.

https://pcpartpicker.com/list/wPdVgL (intel)
https://pcpartpicker.com/list/WQwy7h (AMD)

It’s very possible to find cheapo desktops with skylake/kaby i5s for that price with coupons and whatnot, but most of them don’t have the PSU or space to fit a 1070.

Do you live in an area that has Microcenter, Frys or I forget the third one (not BB). I am an online customer of theirs but the reason I ask is I get flyers from them all the time for some pretty good bargains on build your own combos or barebones… in store only.

If you get a good a good mobo and cpu combination, everything else can be upgraded again later. I usually through the PSU in there because i hate unplugging everything again.

or the completely pre-builts has things like these:


I can’t really vouch for specific brands but they’re out there.

Yeah something like this ought to work, but you would need to upgrade the PSU.

Thing is, he has an ancient sandy bridge piece of shit, but he overclocked it to 4.4Ghz. I doubt a skylake CPU at 2.7Ghz (boosting to 3.3Ghz) would be an upgrade in anything other than power consumption. Really you would need a much faster stock CPU like a 7600 or a K-series (7600K) on an overclocking enthusiast motherboard to offer him a meaningful CPU upgrade.

I tend to agree with Stusser; not convinced his system is holding him back especially if he’s got a 1070. Have you seen the FPS he’s concerned about? Try high instead of ultra settings.

Oh man my bad I totally missed this important point @stusser. Yeah if he has a 1070 just back off the ultra wankery!

Are you sure though. My i5-3570k is a minimum on one of the newer games. the 2500k hit min on titles some time ago. It could easily hold the system back for some games.

It’s old, but it’s clocked at 4.4 Ghz. Each generation offers a 1-14% instructions per-clock (IPC) upgrade.

Looking at Crysis 3 numbers.

Sandy: 100% performance
Ivy is 7%: 107%
Haswell is 14%: 121%
Broadwell is 2%: 123%
Skylake is 10%: 133%
Kaby is 1%: 134%

So we’re looking at a 34% IPC improvement from that ancient CPU. His 4.4Ghz Sandy Bridge is equivalent to a 3.3Ghz Kaby Lake. So something like an i5-7500 would be a mere 15% upgrade at its max boost clocks.

That’s why I said there are no great upgrade paths unless he overclocks. Even a 7600K would only be a 27% upgrade at max boost clock of 4.2Ghz.

Now if you get a 7600K and overclock it to 5Ghz, that’s a 52% upgrade, and that’s something you’ll notice.

I’m using a 2500k and a 1070 driving a 1440 monitor and it’s great. Decent OC on the 2500…3.9 maybe?

Hey I popped in an RX480 and can do everything I mostly want too. I think the only game I’ve heard that might tax my build is MA Adromeda which lists it as the min, and ARK which is horrifically optimized. I am guessing Conan might have issues too when I get around to it… issues as in I have to drop settings not that i can’t play.

I’d definitely love to upgrade. This machine is 4 years old now. I’m just waiting for a point where it makes sense to do so.

I wanted to thank everyone in this thread again for all the advice. I’m having a chat with my son later to find out exactly why he feels he is CPU bound, what type of games bother him and talk him through the pros and cons of upgrading this gen (including the likely relatively limited CPU impact without going really high end). We’ll see whether he wants to pull the trigger or maybe wait another gen.