Howdy, Stranger!
It looks like you're new here. If you want to get involved, click one of these buttons!
Quick Links
GPU overclocking, save till where..?
My old EVGA GTX460 SC has broken down, and I'm not sure if it's because of the overclocking I did or that it as because of the Neverwinter (online) overheating bug in DX9. Anyway, EVGA was good enough to replace it with a GTX660 after a couple of faulty RMAs (which went into my son's PC, and I took his ASUS GTX460 to get SLi again, which is faster than the GTX660 
).
Now with my GTX460 SLI back in place here's my current configuration:
Asus EN GTX 460 Direct CU TOP/2DI/768MD5 - factory clocked @ 700Mhz
EVGA GTX460 SC - factory clocked @ 763Mhz
This combination was in SLI in my system before I had 2 identical EVGA cards, and back then I was clocking the ASUS card on 763Mhz to match the EVGA card. That was a totally stable configuration back then.
When I found the 2nd (and similar) EVGA card I clocked them on 867Mhz and it appeared stable. After having some problems with certain games (Neverwinter, The Sims 3) I clocked the speed back to 850Mhz and that seemed stable too. In the end the oldest EVGA card broke down after it had run on 850Mhz for a year or so (after clocking the speed down to 825Mhz)
At this moment I'm running the ASUS and EVGA cards on 825Mhz. I know that this EVGA card can easily handle this speed, but I am a bit concerned though for the ASUS card. Mostly since it's now overclocked close to 20% of it's factory default setting.
So I'm wondering up to what speed I can safely overclock my GPUs (the ASUS mostly). The extra boost from 763Mhz to 825Mhz is nice, but if I risk the card to break down at this speed I'd rather not take the extra speed boost...
Comments
I think the "safe" zone so to speak will vary with each card.
No one here will be able to tell you a definitive Mhz OC that will be safe for your cards. Those cards run hot and any OC is going to increase that, which will decrease the life of the hardware. If you have already had one card go bad and are still using one older card with a newer card then there is no telling how long they will last at stock speeds, much less OCd.
If it were me I would probably put a small OC on them and let them be. You are gaining some benefit from a bigger OC for sure, only you can decide if the risk of failed hardware or a little bigger OC is worth it. If you dont or cant replace them if one or both fail then a small OC or no OC is the way to go.
Overclocks aren't static.
Maybe when the card is new you can get 200Mhz.
A year later maybe 150Mhz.
A year later 25Mhz.
They change, as the silicon degrades, and dirt/dust builds up on the heat sinks, and voltage regulation starts to degrade, and a million other factors.
You just have to re-adjust your overclocking when you notice irregularities, like crashes, artifacts, BSODs, etc.
That is why the first step of troubleshooting is always "If your overclocking, go back to stock clocks".
Speed is never an issue - if it were only speed you had to worry about, you could clock them to 100 Bajillion and leave them. It's heat you have to watch out for, and once you start getting crazy fast, stability issues.
Watch the thermals on the cards, I would try to keep them well under 80C under your highest load. I think they are specced to go upwards of 95C, but the hotter you run them the more your really accelerating the breakdown.
As I said in my OP, I'm still not sure if the oldest card dies because of the overheating from Neverwinter (more ppl complained about extremely hot temps) or overclocking (both core & memory).
The 'newer' card in that old configuration was the 'slave' card and is now again the 'slave' card and I doubt it'll have had real negative effects of the one that broke down.
In the mean time I've changed PC case, now with PSU at the bottom, blowing air up and it has resulted in a dramatic temp drop. Where the old PC case made the cards run hot, but still within safety limits, now the cards just stay cool at 70C when running on 99% for half an hour (or even longer). So I guess the temp problem that comes with OCing is no longer one for me
I do however realize that upping the speed can damage the cards as well. And as you said, the gain of that 8% is nice (and noticeble in certain games), it's not really worth the risk. Right after posting this message, I've clocked both GPUs on 763Mhz, just to be on the safe side ;-)