Safe vCore Settings

Adeptus Titanicus

I've got a very stable OC of 3.6GHz on a P43.0C with the vCore set at the minimum for the board, 1.53v (if i recall correctly). Very happy with that.

But of course it's just never enough! I have tried an FSB of 247, 248 and 250, and the only way i can get it to run for any amount of time at this level is if I up the vCore to 1.7v. ANything lower and the system locks up after running prime for 5-10 mins. I'm currently priming at 247 at 1.7v with the RAM at 5:4, to be sure I am testing the CPU properly, and so far so good.

I did this a while ago (under the influence ) and someone commented that I was brave (:p). Is this dodgy? I see in some OC databases that people have all sorts of high voltages, and as the chip says 1.55 max, I'm a little... unsure...

CPU temp is maxing at 56 with this voltage, a good 5 degrees hotter than when the vCore it at its lowest, but I'm still in safe territory.

Any opinions/advice? Will I end up with a China Syndrome in my case?

"Today, only a handful of people know what it means... Soon you will know."

Col_Loki

If you had an XP id say up the voltage to 2v and happy hunting!! Its different with the P4's , lower temps & voltage are acceptable. Ive heard of some instant deaths on P4's but this generally with older revisions and 1.85v+ running 24/7 with this setting.

This question is far better suited to the intel heads that float round these boards so i wont go much further . Its nice to be able to have lets say 3.8ghz on high voltage for benchmarks or showing off isint it , 3.6v on 1.53v is very nice and not within the slightest bit risky!!

BTW ive tried overclocking when "under the influence" and some of my best work was done there . But i did try my Xp2500+ @ over 3ghz and locked up the whole system (slight misscalculation eh :rolleyes: ).

Sir Random

I wouldn't run it 24/7 at 1.7v on air, P4s have suffered sudden death from overvolting . Highest I've taken mine was 1.65v (to break 4Ghz).

unkel

Originally posted by Sir Random
I wouldn't run it 24/7 at 1.7v on air, P4s have suffered sudden death from overvolting

Not at all

You're grand running at 1.7V - P4C won't die, just slow down when overheated

Ok, the cpu might not last 20 years, but how relevant is that?

Go for it m8 - happy overclocking

P.S. amazed at the overclock you're getting already at stock voltage :eek:

Adeptus Titanicus

K, had it at 1.7v, 247FSB running Prime last night, but it only ran for about an hour before the system locked up. As I mentioned before, the temps look pretty ok, I was just wondering would something else get zapped. Might do like Random did and pop it right up for the hell of it, just to get some benchmarks at that speed. (was your 4GHz stable at that voltage Random?) Actually, I haven't benchmarked it at all at 3.7GHz. Might do that before running Prime again.

I'll try a slightly lower FSB at 1.7 and see how it goes. Is it worth risking upping the vCore a little more?

And yep! I'm fairly pleased at my 3.6GHz at stock voltages! I shouldn't be so greedy!:)

unkel

Originally posted by Adeptus Titanicus
I'll try a slightly lower FSB at 1.7 and see how it goes. Is it worth risking upping the vCore a little more?

Sure just for the crack. Like I said, you're not gambling with the life of your cpu

Originally posted by Adeptus Titanicus
I shouldn't be so greedy!:)

It's only natural

Sir Random

Originally posted by unkel

quote:

---

Originally posted by Adeptus Titanicus
Is it worth risking upping the vCore a little more?

---

Sure just for the crack. Like I said, you're not gambling with the life of your cpu

How can you advise someone to go over 1.7v so flippantly? Never heard of SNDS? He will be gambling with the life of his cpu if he runs it over 1.7v 24/7 on air. If not, we'd all be doing it.

Sir Random

Originally posted by Adeptus Titanicus
Might do like Random did and pop it right up for the hell of it, just to get some benchmarks at that speed. (was your 4GHz stable at that voltage Random?)

I never set my vcore above 1.65v in the BIOS, and 4Ghz wasn't stable (just did minor benches).

Adeptus Titanicus

Originally posted by Sir Random
I never set my vcore above 1.65v in the BIOS, and 4Ghz wasn't stable (just did minor benches).

k, thanks. Like I said, I never benched it at 3.7, so I might just do that. TBH I wouldn't feel too safe about running it 24/7 on 1.7, so it's just for the sake of seeing how high I could potentially go. Do you think the main issue would be heat? i.e., if I had water colling would it be safer? Or do you think it is it just a case that running it this high is just not good for it?

Thanks for the opinions guys. But be assured, I won't be rushing into popping my vCore up to 2 or something..

PS, what's SNDS? I'm pretty sure it's not the Sisters of Notre Dame, or Special Needs Design Services..

unkel

Originally posted by Sir Random
How can you advise someone to go over 1.7v so flippantly? Never heard of SNDS? He will be gambling with the life of his cpu if he runs it over 1.7v 24/7 on air. If not, we'd all be doing it.

Obviously I'm not advising to just up the voltage from 1.5 to 1.8 volt, not check the temperatures and then leave the house for the weekend :dunno:

Upping the vcore in small steps while keeping a good eye on the temps on a P4C with good air cooling and then leaving it @1.7V provided all is well under load will not lead to cpu failure. SNDS is very rare anyway on P4C unlike it's predecessor and even more so at just 1.7V

Adeptus Titanicus

Well, I ran a load of benchmarks on it this evening t 3.75GHz.

Tried 250 FSB on 1.7v with the RAM at 5:4 2.5-3-3-7 @ 2.65v
then 250 FSB on 1.7v with the RAM at 1:1 at 3-4-4-8 @ 2.65v as it didn't seem to want to boot at tighter timings. Might try it again later.

The thing is it ran very well for 2 each of 3D01, 3D03 and Aqua03 (benched each twice, one without the gfx o/c (9800XT stock levels) and one with an o/c(327.5/405)). I'll try prime again with these settings. Timings can make a big difference with some of these benches...

Anyway, just in case anyone's interested

Stock everything for reference
200 FSB RAM @ 1:1 2.5-3-3-7, gfx @ 9800XT stock
3DMark01: 17,691
3DMark03: 6,439
Aqua03: 44,997
SuperPi: 47secs

My normal OC
240 FSB, RAM @ 1:1 2.5-3-3-7, gfx @ 9800XT stock
3DMark01: 19,911
3DMark03: 6,612
Aqua03: 48,108
SuperPi: 40secs

250 FSB RAM @ 5:4 2.5-3-3-7, gfx @ 9800XT stock
3DMark01: 19,987
3DMark03: 6,610
Aqua03: 47,839
SuperPi: 39secs

250 FSB RAM @ 1:1 3-4-4-8, gfx @ 9800XT stock
3DMark01: 20,234
3DMark03: 6,632
Aqua03: 48,136
SuperPi: 39secs

So, at a 5:4 ratio, going up to 250FSB doesn't give me much of a boost. Likewise, 1:1 at 250 with looser timings don't really amount to alot either, just a couple of hundred marks on Aqua03 and 3D01, but still a little better than 5:4. I'll try with tighter timings again after the weekend (taking a well-earned break ). I'd say tighter timings will make a bit of a difference. Any suggestions bearing in mind it's the 3700 Rev2?


Oh, and here's the 250 with the gfx upped a bit as a matter of interest
250 FSB RAM @ 1:1 3-4-4-8, gfx @ 327.5/405
3DMark01: 20,716
3DMark03: 6,991
Aqua03: 50,029

unkel

Adeptus Titanicus, interesting results

What was vcore during the testing? It looks like your normal overclock is pretty much optimal. With the P4C and high FSB settings, most people (including myself) would report that running the ram at 1:1 is best if the timings are ok for high speed memory. Most benchmarks online only compare low speed, tight BH5 2,2,2,5 to high speed loose 3,4,4,8 and don't report as what seems to be best for P4: high speed, tight enough 2.5 memory

Your ram is obviously holding you back a little although I'm amazed it runs as PC4000 with loosened timings. If you had my PC4200 OCZ, you'd surely do 250FSB or more with 2.5,3,3,7 or 2.5,4,4,7. How far would that let you go?

Your mobo/cpu combo is working better than mine. I can run XP @250 and can run some benchmarks, but no prime 95 stability

Adeptus Titanicus

Originally posted by unkel
What was vcore during the testing?
...

Your ram is obviously holding you back a little although I'm amazed it runs as PC4000 with loosened timings. If you had my PC4200 OCZ, you'd surely do 250FSB or more with 2.5,3,3,7 or 2.5,4,4,7. How far would that let you go?

Your mobo/cpu combo is working better than mine. I can run XP @250 and can run some benchmarks, but no prime 95 stability

Ah, but I never said it was prime stable Actually, I don;t know if it is or not at these settings. When I first started overclocking this I tried 250, but it wasn't prime stable, but I hadn't messed with the timings, so I'll have to run that again. Like I said though, it ran 6 benchmarks no problem, while when I had it at tighter timings the first test I ran, Aqua03, froze up.

vCore at 250 was 1.7v, otherwise 1.55v. Temps during benching never went above 51.

I might try slightly tighter timings too. 2.5-4-4-7 looks interesting. I know from experimenting that going from 2.5-4-4-8 to 2.5-3-3-7 at stock speeds makes a fair difference.

Ta

AT