What is a 6800NU? A vanilla 6800? Overclocking questions too...

[Ichinisan]

Good freakin' God. I've been reading about BIOS modifications and volt-modding all day and I can't get any clarity on this. Google can't seem to answer my question. Is a 6800NU a plain-jane GeForce 6800? As in, "non-Ultra"? If so, that's a stupid way to put it... a 6800GT is also a "non-Ultra".

 

[theMan]

yeah, its just a plain 6800. "NVIDIA Geforce 6800" also, only the AGP ones mod, but im sure you know that.

 

[Ichinisan]

Originally posted by: theman
yeah, its just a plain 6800. "NVIDIA Geforce 6800" also, only the AGP ones mod, but im sure you know that.

Thans. Yep, already unlocked it too (Fourth card worked). 😉 Now I'm just looking for some decent overclocks. I didn't realize it was regular DDR and clocked so low compared to the 6600GT I am replacing. A larger manufacturing process too! I guess it'll take some serious measures to OC this badboy so I'll be BIOS-modding it to a higher voltage if possible. Should I aim for a high memory overclock considering that it's not GDDR3? Should I aim for maximum GPU speed instead considering that it's 256bit bus?

There don't seem to be any 6800 BIOS files here but it still seems to be an awesome place to start. Any other recomendations?

 

[LOUISSSSS]

my 6800 AGP is clocked at 384/790 on stock cooling

 

[Ichinisan]

Originally posted by: LOUISSSSS
my 6800 AGP is clocked at 384/790 on stock cooling

Did you do anything special to reach that? Mine flakes out if I move too far from the default clocks in either direction (Underclocking or overclocking). I'm using RivaTuner, which will not let you save the OC unless it passes a quick test (Screen flashes for a sec). My memory starts getting flaky in the 760s but I can get it to the 770s by repeatedly testing until it passes once. My GPU can't go near your speeds either. I assume everything needs more voltage (Cooling should be the issue considering that this is being done from a desktop app and not an intensive game).

Because these cores are intended for GTs/Ultras and binned because of bad pipes (Though some unlock), the core itself can't be the limiting factor in it's OC abilities as long as I am still well under GT speeds. So what is? It has the same cooler. The GPU and memory operate asynchronously, right? In other words, I'm not silently OCing the memory by raising the GPU clock, right? I'm sure the voltage is much lower and that is what it needs more of to reach GT speeds. The cooler looks like it can certainly handle it! I hope I'm not barking up the wrong tree here with this BIOS modding stuff that I haven't gotten started on (I'm studying for the rest of today and tomorrow). I'd like to know how everyone else got their results before I start in a couple days so I can avoid wasting time.

BTW, eVGA is the manufacturer that will let you OC as much as you want within warranty, right? As in, you could fry the card and they will replace it IIRC.

 

[mwmorph]

btw, the low clocks are not directly comparable to your old 6600gt.

a 6600gt has a 128bit bus while the 6800 hasa 256bit bus.
the 6800 memory at 501mhz will have more bandwith than a 6600gt at 1000mhz due to bus width so at 700mhz, you already have 40% more bandwith.

so anyway, the core is still memory limited. Just look at how well the 6800gs does with a higher memory clock and more video ram(the 6800 nv40 core was designed for 256mb). I did a test the 6800gs unlocked to 16pipes and downclocked to 325/700 does 4200 3dmark05s. A 6800 unlocked at stock 325/700 speeds does ~3800 4dmark 05s meaning it is still limited by memory. Also, since yoyu have essentially a 6800gt or 6800 ultra core, paired with 700mhz memory, not the 1ghz or 1.1ghz that this core was designed for, it will be a bottneck.