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ozzuneoj
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Vintage Computer Overclocking: i5 2500K

Thu Jul 27, 2017 11:21 pm

Thread title is (mostly) sarcastic... I have a 2500K and since the upgrade itch has been hitting me lately I decide to try pushing my overclock a little further, rather than spend any money.

I tried hitting 4.5Ghz again a few months ago and decided against it since my temps went up substantially and I wasn't too pleased with that. A few days ago I thought about the fact that my poor CPU has been squashed under the old Thermalright Ultra 120 Extreme with an aging layer of AS5 to keep it happy. I figured it'd be a good idea to reapply some newer thermal paste, since I'd read that Cryorig's CP7 (which came with the H7 I put in my HTPC) is actually a bit better than AS5.

Before touching anything, my system was at 4.2Ghz, vcore set to 1.3v (vdroop set to auto)... been that way for years. After running the Intel Burn Test on Maximum for a few runs the highest my core temps (as reported by HWiNFO) hit were 66,68,74,67.

After changing the paste, lots of UEFI tweaking, re-reasearching how to overclock a Sandy properly and even adding some creative duct-work in my case to ensure that cool air was being drawn in through the right places and hot air was being blown out, I was able to get the chip to happily run at 4.5Ghz with 1.35v (vdroop set to low now), with several power saving features still enabled. After 5 runs of IBT at maximum and an hour of Prime95 small FFT, my highest peak core temps were 64,68,75,67. A very respectable result, considering the boost in voltage and clock speed. The best part is that it was about 15F warmer in my office during the second round of tests as well. After several hours of gaming the temps topped out at 60, with most cores being in the mid 50s.

So, I'm happy with this result. I ran Passmark and its reporting a solid 10% improvement over my previous run at 4.2Ghz in single threaded tests. It actually scored a bit better than the average single thread score for a stock 7600K, which is cool.

But, now... the real question is where should I stop? If under normal conditions when its 80F in my office my CPU is topping out at 60C in games, it seems like I have plenty of head room left... I'm just not sure how much voltage it would take to go higher and how rapidly the temperatures will go up. My idle temps are still in the high 20s to low 30s and power consumption drops nicely at idle, so I doubt I'll be frying my CPU with hours upon hours of heavy loads at high voltages, but I don't want to kill the poor fella. I've read about plenty of people running upward of 1.4v with these, and I played with it a little and couldn't get the thing stable at 4.7Ghz, but I've done a lot of tweaks since then.

Along these same lines, how far can I realistically take the memory voltage? I have some really nice GSkill Ares 2133 DDR3 that I bought to run it at 1866 at 1.5v (since I was under the impression that SB shouldn't run any higher voltage memory), but I have been reading of a lot of people using 1.6v on SB without any issues. Has anyone here had any experience with this? After many years of use are people's Sandy Bridge systems showing any signs of failure due to 1.5v+ memory or 1.4v vcore?

As a side note, I finally found a use for a huge Delta 120x38mm fan I stole out of an old system years ago. I have a fan adapter that allows me to plug fans into either 5v or 12v, and when I hook it up to 5v it actually runs at a reasonably level. On 12v it is so loud and fast its kind of scary (easily 3500 RPM)... its the kind of fan that I genuinely worry about getting injured by when testing it outside a case. I decided to use it as my rear exhaust fan and it moves so much air, its wonderful (far more than the stock coolermaster fan). Though, now I'm wondering if I should be using it as my CPU fan instead. :o
Desktop - i5 2500K@4.5Ghz - MSI P67A-G43 - 16GB DDR3-2133 - PNY GTX 970 - Samsung SM841 128GB
Laptop - Asus Q500A - Core i5 3210M - 8GB DDR3-1600 - 840 EVO 256GB - AUO 1080P
HTPC - i7 4790 - Asus B85 - 8GB DDR3-1600 - 64GB Crucial C300 - EVGA GTX 1050 Ti
 
f0d
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Re: Vintage Computer Overclocking: i5 2500K

Thu Jul 27, 2017 11:28 pm

im generally considered crazy by the "average" overclocker but have had sandy class cpu's at 1.5v+ for months encoding videos with handbrake without issues so i dont think 1.4 is too insane to give a go

when i saw vintage overclocking i was thinking z80 or 8051's lol :P
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Ifalna
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Re: Vintage Computer Overclocking: i5 2500K

Thu Jul 27, 2017 11:41 pm

Just experiment.
You will find a point of diminishing returns, where you'll need A LOT more voltage for very little gain.
My Ivy runs at 4.6G @ 1.3V. Temps during gaming are typically in the low 60s. (I don't care for unrealistic IBT temps past initial testing)

4.8 has been possible but I'd need to jump to over 1.4V and temps at that voltage are out of the question, even for my NH-D14. I could probably run that with a custom loop but I consider it too much effort for an additional 200MHZ.

I never bothered with RAM overclocking, becaus on Ivy/Sandy RAM speed was pretty irrelevant compared to today's chips or past generations. So I plugged in 1.5V 1600 RAM and forgot about it. Most XMP RAM back in the day operated with 1.65V btw.
The backbone of modern industrial society is, and for the foreseeable future will be, the use of electrical Power.
 
ozzuneoj
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Re: Vintage Computer Overclocking: i5 2500K

Thu Jul 27, 2017 11:45 pm

f0d wrote:
im generally considered crazy by the "average" overclocker but have had sandy class cpu's at 1.5v+ for months encoding videos with handbrake without issues so i dont think 1.4 is too insane to give a go

when i saw vintage overclocking i was thinking z80 or 8051's lol :P

Yipes! 1.5v and doing encoding? These things sure are durable. Its a shame they couldn't just implement some of the improvements of the modern chips without losing the wonderful thermal performance of the older ones. I know Kaby Lake performs better but due to the high temps I must say... I would take a (Sandy) Bridge over troubled waters (Lakes)... (not really, I'd love a brand new system... just thought that sounded good).

And yes, just in case there is any confusion, I was totally not serious about the 2500K being vintage. There is a tricked-out IBM 5150 right next to my main system, but sadly isn't too easy to overclock. The most I've done to that is I dropped in an ISA card with a 7Mhz 286 to double performance. :O
Desktop - i5 2500K@4.5Ghz - MSI P67A-G43 - 16GB DDR3-2133 - PNY GTX 970 - Samsung SM841 128GB
Laptop - Asus Q500A - Core i5 3210M - 8GB DDR3-1600 - 840 EVO 256GB - AUO 1080P
HTPC - i7 4790 - Asus B85 - 8GB DDR3-1600 - 64GB Crucial C300 - EVGA GTX 1050 Ti
 
f0d
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Re: Vintage Computer Overclocking: i5 2500K

Fri Jul 28, 2017 12:02 am

when i was doing 1.5v+ on my 3930k the vrm's needed some pretty good cooling so i suggest if you do start going above 1.4v that you actively cool the vrm heatsinks with some fans
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also i have done 1.7v on my ram but again im a little nuts so you probably dont want to go that far
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ozzuneoj
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Re: Vintage Computer Overclocking: i5 2500K

Sat Jul 29, 2017 9:04 pm

Well, I rearranged my fans a bit and tried pushing the overclock a little farther... and I can get it to boot windows and work at 4.7 quite easily, but it seems like its going to take quite a big increase in voltage to actually keep it stable. So I guess I'll be content with 4.5 for now. Instead of pushing the clock speed higher, I decided to apply my memory's XMP profile of 2133 10-12-12-31 1T at 1.6v. So far it seems stable. I ran memtest 86+ for one full pass and it had no problems.

If I do have instability, what is it that likely needs tweaked? I have read that in some cases it can be hard to get Sandy Bridge stable with 2133Mhz DDR3. Would increased memory voltage be necessary? Or something else?

BTW, when I rearranged my fans I ended up putting my Cougar Vortex on my GTX 970 (it has an Arctic Accelero S3 "passive" cooler) and it keeps it icy now. I overclocked my cheapo PNY 970 to +175Mhz core and +500Mhz memory (seems to hang around 1415Mhz core, 8000Mhz memory). This should give me a pretty solid boost in graphics performance too.

All in all, for just some time spent having fun messing with cooling and tweaking settings, I should have ~10% more CPU performance, ~10-12% more GPU performance and 16% more memory bandwidth. Not bad on an "old" system that is already overclocked. Its crazy to think about how much more performance I have over stock settings. 4.5Ghz all-core is 800Mhz over the max single core turbo frequency of my CPU and 1200Mhz over the non-turbo clock... that's up to 36% more performance. And right now its idling at 31C and it tops out at 60 on the hottest core during gaming. If someone could release another CPU like this, I'd be all over it. No one seems capable of doing this anymore though. Too much heat, stock clocks are already sky-high with little room for overclocking... its too bad. I have my hopes up for the next revision of Zen to give some serious overclocking room (and an actually performance increase to make it worth it).

Till then, I'll try to be content with my 2500K. I'm still keeping my eyes peeled for a delidded 3770K, 2600K or 2700K for cheap though. Four more threads couldn't hurt. :)
Desktop - i5 2500K@4.5Ghz - MSI P67A-G43 - 16GB DDR3-2133 - PNY GTX 970 - Samsung SM841 128GB
Laptop - Asus Q500A - Core i5 3210M - 8GB DDR3-1600 - 840 EVO 256GB - AUO 1080P
HTPC - i7 4790 - Asus B85 - 8GB DDR3-1600 - 64GB Crucial C300 - EVGA GTX 1050 Ti
 
TwistedKestrel
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Re: Vintage Computer Overclocking: i5 2500K

Sat Jul 29, 2017 9:57 pm

Two big things that took me a while to figure out about Sandy Bridge overclocking:

-VID is not Vcore. VID is what CPU-Z, Realtemp, Coretemp will show you - it is the voltage the CPU is requesting. Depending on how you have adjusted Vcore, it could be above or below the actual voltage.

-If you set your overclock through gradual increments of voltage/frequency, LLC does not help at all (you will wind up at the same voltage at 100% load). You might as well just leave it off so you have a clearer picture of the voltage you're commanding (and reaching, since you are now monitoring Vcore)
 
Starfalcon
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Re: Vintage Computer Overclocking: i5 2500K

Mon Aug 21, 2017 10:59 pm

I used a 80x38 EHE delta on my OCed 2500 athlon XP systems for years, and it was loud as hell 52 Db and ran 5.5k rpm or so. kept the proc extremely cool though, at the price of hearing loss :( . Although that fan didnt have anything on the 60x38 8k rpm delta I used for a previous build 62 Db of ear bleeding happiness...
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Abit BP6 2X 300A@450 mhz, 1.5 GB PC133 ECC, Renditon Verite V2200, SB AWE32, Adaptec 2940U2W, 4.3GB Quantum Atlas 10K, Plextor Ultraplex
 
DrDominodog51
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Re: Vintage Computer Overclocking: i5 2500K

Mon Aug 21, 2017 11:16 pm

f0d wrote:
im generally considered crazy by the "average" overclocker but have had sandy class cpu's at 1.5v+ for months encoding videos with handbrake without issues so i dont think 1.4 is too insane to give a go.

I won't call you crazy, but 1.5V does degrade Sandys over time.

That said; I've pushed 1.6V through Haswell (on air) for benchmark suicide runs.

f0d wrote:
also i have done 1.7v on my ram but again im a little nuts so you probably dont want to go that far

Nah. That's actually pretty sane. 1.8V is the minimum that will kill any DDR3, and some ICs will scale with additional voltage up to 2.2V.

To address the OP, 1.4V VCore should be safe on Sandy, Sandy Bridge CPUs should be kept below 75C.

Edit: I just saw the dates on the posts above Starfalcon's.

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