Upgrading from i5 2500k

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JimmiG

Platinum Member
Feb 24, 2005
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I upgraded from a 2500 to a 6700k, mainly because my sata3 ports had died on my old motherboard. my 2500 was running at 3.8ghz turbo, and the 6700k is currently at 4.5ghz. There is definitely a noticable difference, mostly in minimum framerates, though average/max didnt change a ton. The biggest change is the platform upgrade, now having all sata3 ports, M.2 for a future upgrade, usb 3.1 type-A and C ports, better onboard sound, etc...

In the end it all depends on the games you play. Some are more dependent on CPU, some on GPU. I think a lot of the performance increases i got were going from a non-K to a K processor and overclocking it gaining an extra 700mhz raw speed. Throw in the 4 generations of 5-10% IPC improvement and to me, it was a worthwhile investment.

The biggest difference likely came from the higher clock speed. Had the 2500K been OC'd to 4.5 GHz (very doable on SB), it would have been much closer. If you had a 2600K rather than a 2500K, the addition of HT would have put it within spitting distance of the 6700K.
 
Aug 11, 2008
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The biggest difference likely came from the higher clock speed. Had the 2500K been OC'd to 4.5 GHz (very doable on SB), it would have been much closer. If you had a 2600K rather than a 2500K, the addition of HT would have put it within spitting distance of the 6700K.

Not sure what you call "spitting distance", but at same clock, skylake is about 20 to 30 percent faster than Sandy Bridge in most cases. The 2500k also lacks hyperthreading which holds it back in some games.

Both seem to overclock to around 4.5 fairly consistently also. So going to a 6700k at 4.5 could give about 40% or so upgrade in games that can utilize hyperthreading over 2500k at the same clock.

My take is anything older than SB is definitely upgrade territory, SB/IB is on the edge of being worth it, and haswell of course is not worth it. That is if you play the latest cpu demanding games and have a powerful gpu. Personally I play mostly older games and have a weak video card, so I am perfectly satisfied with my stock i5 at 3ghz.
 

Sheep221

Golden Member
Oct 28, 2012
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The higher IPC of skylake is mostly seen in terms of lower TDP, skylake locked SKUs peaked at 65W TDP and are as fast as 95W sandies, so yes, their IPC is higher by some 30% but they are faster maybe by few percent at best. The unlocked SKUs are only faster if they are heavily overclocked, especially the i7. Seems that only good skylake upgrade over quad core i5 of any previous generation is 6700K that has to be overclocked.
It's kinda smart move from Intel since most quad cores are now 65W or lower, they can move to 6-8 core 95W SKUs and 12+ core 130W SKUs for Skylake-E and KL/CL architectures.
 

WilliamM2

Platinum Member
Jun 14, 2012
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I moved my Windows 10 install from my 2600k setup to my 6700k and it detected new hardware, booted right up and stayed activated. I think it depends on what kind of key you used for the upgrade (retail vs OEM ... mine was a free student key from my college)

I went from a 2500K to a 6600K. I had previously upgraded from a retail Windows 7 Ultimate to 10, It immediately told me windows was not activated, and refused to activate.

I was afraid that would happen, and it's one of the reasons I updated my system this year. Normally I would have waited one more.
 

BonzaiDuck

Lifer
Jun 30, 2004
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That's a load of interesting observations, folks!

The 2600K runs at 4.7Ghz, and I can run the 2700K at 4.8 provided I like what I see in the maximum VID and maximum -- unloaded Turbo -- voltages. The temperatures will go up slightly, but it's well within the Tj self-managed shutdown limit, and just a bit above the TCASE spec for "thermal guidelines." In fact, except for stress-testing the overclock setting, either the high-core or the average would be within that latter ~73C spec for games at most.

So . . .i7-6700K, lower power-consumption, perhaps a 20-30% boost in performance over what exactly? The 2500K's 4.5Ghz clock?

There are a lot of us out there who spend time daily dickering with hardware and software, networks, servers and media, but who see the sense in keeping control of the purse-strings. There's a large market in refurb corporate IT assets; a large market for used parts and surplus stock.

I'll have to buy the Corsair Vengeance C70, a Corsair Hydro 115i, a motherboard, dual or quad-channel RAM, and the processor. I've got the PSU brand-new in the Seasonic carton, a Skylake would have the Intel graphics and I have spare dGPUs that are dated but work. I've got spare disks, and other parts. I think I can do that initially for $1,000. I usually spend over $1,500 on these projects, and I will eventually on this one, but testing, OC'ing -- tuning -- and software installations or fixing loose event-log anomalies is best done up-front. The system wouldn't need to "go online" until a year from now.

Somehow, I just think all of this is sort of like surfing in certain locations looking for particular years when the waves are highest. It's also about money versus existing performance. It doesn't even hurt to stay a year behind the technical edge of newly released hardware.

It could also be fun the take about $3,000, build a dream machine now, sell off my parts to either friends or "Shopping"->"For Sale or Trade." That's still going to cost more than it needs to.

So I'll stick with my plan.
 
Aug 11, 2008
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The higher IPC of skylake is mostly seen in terms of lower TDP, skylake locked SKUs peaked at 65W TDP and are as fast as 95W sandies, so yes, their IPC is higher by some 30% but they are faster maybe by few percent at best. The unlocked SKUs are only faster if they are heavily overclocked, especially the i7. Seems that only good skylake upgrade over quad core i5 of any previous generation is 6700K that has to be overclocked.
It's kinda smart move from Intel since most quad cores are now 65W or lower, they can move to 6-8 core 95W SKUs and 12+ core 130W SKUs for Skylake-E and KL/CL architectures.

Seems like you are mixing terms here. Ipc and tdp are not directly related. If skylake IPC is 30% faster than sandy bridge, then at the same clockspeed, skylake will be 30% faster. The lower tdp is a separate issue, and actually another advantage. You dont sacrifice the ipc advantage because the tdp is lower, unless the lower tdp is obtained by lowering the frequency.

I would however agree that to get a worthwhile upgrade to a highly overclocked sandy i5 one needs to go to 6700k, so that you get both the benefir of hyperthreading and higher ipc.
 

Zodiark1593

Platinum Member
Oct 21, 2012
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I was recently debating selling my 4590 (forced at full turbo) for an i7 myself. I do a fair amount of tasks that could benefit from more threads, but I'm on the edge of being able to justify getting a 4790(K). I'd love a 5775C as it seems to be about on par with the 6770, though the igp would go largely underutilized, and that price.
 

Sonikku13

Member
Jun 16, 2009
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I would say the i5 2500K and the i7 2600K, both overclocked moderately, say, 4.5 GHz, are the benchmarks to go by. If you can't get much of an improvement out of an i7 6700K, it's not worth upgrading. Might as well wait.
 

Sheep221

Golden Member
Oct 28, 2012
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Seems like you are mixing terms here. Ipc and tdp are not directly related. If skylake IPC is 30% faster than sandy bridge, then at the same clockspeed, skylake will be 30% faster. The lower tdp is a separate issue, and actually another advantage. You dont sacrifice the ipc advantage because the tdp is lower, unless the lower tdp is obtained by lowering the frequency.

I would however agree that to get a worthwhile upgrade to a highly overclocked sandy i5 one needs to go to 6700k, so that you get both the benefir of hyperthreading and higher ipc.

I know, they are not directly related - technically, but since they did increase the IPC in the architecture, the quad cores are now clocked lower, unlike the dual core i3s, which are much better in this sense, are clocked higher and are much faster than i3 sandies/clarkdales. Anyway I get back to what I said before, the advertised average 30% increase is possible only with greatly overclocked unlocked i7.
 
Aug 11, 2008
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I know, they are not directly related - technically, but since they did increase the IPC in the architecture, the quad cores are now clocked lower, unlike the dual core i3s, which are much better in this sense, are clocked higher and are much faster than i3 sandies/clarkdales. Anyway I get back to what I said before, the advertised average 30% increase is possible only with greatly overclocked unlocked i7.

Well, obviously, if you compare a stock 6500 to a highly overclocked 2500k, it wont be 30% faster. But you are still muddling the issue looking at multiple variables at the same time.

IPC gains, (estimated, based on the workload obviously)

SB to IB 5%
IB to Haswell 10 %
Haswell to Skylake 10% (?? need fast ram, but with overclocked system, you will most like have that)

That is roughly 27% *without* considering hyperthreading, for a 2500k vs 6600k overclocked to the same frequency, and skylake seems to be able to come close to Sandy overclock. Now is that gain a worthwhile upgrade? That is up to the user. All I am saying is that you dont have to include hyperthreading to see a 25 to 30 percent gain from SB to Skylake.
 

David_k

Member
Apr 25, 2016
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On digitalfoundry's 2500K video, even OC+fast DDR3 memory frame times were not as good as on the skylake i5 , and the i7-6700k made the gap even bigger, so there is something to consider here..
 

BonzaiDuck

Lifer
Jun 30, 2004
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On digitalfoundry's 2500K video, even OC+fast DDR3 memory frame times were not as good as on the skylake i5 , and the i7-6700k made the gap even bigger, so there is something to consider here..

Depends on whether a 30% gain in some respects should mean end-of-life for your previous investment in hardware. And that all depends on your computer usage and needs.

There are other aspects to the investment. If you invested time and effort into building a rock-solid rig clocked to a reasonable level, that adds something to your reticence.

So there's building and tuning, and there's ongoing use. It's just a matter of how desperate one is for greater performance and "overclocking adventures" to lay out another ~$1,500 to build a new system, versus what you can get for the used SB parts on EBay or the "sale and trade" forum here.

I generally pass down old systems to family members with mainstreamer computing habits. But I just built an i5-3570K system for my brother a year and a half ago, and Moms isn't going to need more than her C2D Wolfdale for quite some time.

I expect to build an i7-6700K by year's end, though. OR -- I'm still in no hurry.
 

MadScientist

Platinum Member
Jul 15, 2001
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Also still running a 2500K at 4.6Ghz, 1.36V with Win 10. Can't remember when I got a BSOD. Like the Duck I upgraded to a GTX 9700.

It still does a decent job running the latest games and I spent so much time tweaking it that I don't feel that upgrade itch yet.