I use Rivatuner and have them set to 650GPU 2026Mem. Fans manual set to 100%.

The cards appear to not be effected in any way by the speed bump and all games run smoothly.

What is the highest safe OC for these cards? realistically of course.

One idles 54-56C, the other 55-59C, load one is 63-68C the other 64-69C.

The highest 3Dmark06 I have gotten is 15,764. That was with the CPU at 3.7Ghz but I normally run it at 3.6Ghz. It passes Orthos at that speed but glitches after awhile at 3.7.

650/2026 is very good/above average overclock. Usually, a strong stock cooled overclock is considered roughly 626/2010.

hmm, I guess I may have already reached a good "safe" speed. I wonder if anyone else has done similar or higher.

Yea, 650/2026 is excellent and probably about topped-out on the core (but wouldn't hurt to try higher ). You may be able to push the mem a bit higher if you have good chips.

Your temps are also very good at that OC. Mine idle at 64-67 and load at 73-76 at 635/2000. I can push them to 648/2100, but I usually like to run a bit cooler/slower for safety.

Ha!, yea thats the evil in my thinking of pushing them higher also but at more than $1200 a set, I'm scared 8O

What got me thinking about higher was that the "new" 8600 - 8500 models are way clocked up like to 675GPU and 700 on the OC models because they have less stream processores. From what I hear their temps are way up also. They are essentially the same G80 type core.

I was thinking my temps are good why can't I ratchet mine UP. I was just wondering if anyone else has done that? Better to learn from some else's experience than my mistakes.....

Here is a good article which shows how different speed settings will actually result in different actual speeds. Looking at their bench results it also explains why the ultra was clocked at 612.
As far as using the 8500/8600 as a guideline keep in mind they are 289m transistors at 80nm vs 681m at 90nm.

very nice, I'm gonna print that out...

Sounds like 611/986 looks pretty safe, which if im reading this right actually yeilds 612/999/1458 ??? Am I reading it right? Are those numbers the same for people who have BFG 8800gtx OC (different bios by bfg?).

Will no guarantee of safe but it looks like a low risk good return overclock.

I tried it out myself and have saved 612/1000 as a profile in ati tool. I let it run scanning for artifacts and have run through 3dmark06 at those settings. I've had no problems and the temps were the same as at stock settings.

So what that says is that theres no point to set the core anywhere between, 618-634. Basically saying, either set your core to 617, OR 635, any thing else in between is useless. Strange thing is, most manufacturers who OC the 8800gtx, are between 626-630. Do they know something we dont, or do we know something they dont? Maybe having 630 on the box sells more cards? Cause by the looks of this... BFG OC2, eVGA superclock/ACS3, XFX XXX, all have the same effective specs, 621/1453/1998, just not advertised as such?

I checked the chart out using everest and its 99% accurate. The cards really do jump like that.

I agree with you're reasoning. Advertising a higher speed is all bragging rights. So if a company advertises an overclocked card hopefully their legal dept. suggested the wording as "clocked at xxx", not "running at xxx".

So what that says is that theres no point to set the core anywhere between, 618-634. Basically saying, either set your core to 617, OR 635, any thing else in between is useless. Strange thing is, most manufacturers who OC the 8800gtx, are between 626-630. Do they know something we dont, or do we know something they dont? Maybe having 630 on the box sells more cards? Cause by the looks of this... BFG OC2, eVGA superclock/ACS3, XFX XXX, all have the same effective specs, 621/1453/1998, just not advertised as such?

I checked the chart out using everest and its 99% accurate. The cards really do jump like that.Well, that's how the shader cores are effected; the TMUs, ROPs, and the rest of the core run at the lower clockspeed.