6800GT RAM overclocking

[Mr. K6]

Since parts for my custom 6800GT HS won't come in until the end of the week, I decided I'd investigate overclocking the RAM. Off hand I'm rather perplexed by the 6800GT's overclocking. I've overclocked man cards before, from Ti4200's to 9800Pro's and GeForce2MX's etc etc. All showed the same results, core too high, snoflakes, RAM too high, missing textures, flickering, etc. Now my GT in either case, when clocked past a point, just starts freezing, be it half-life 2 or 3dMark05. Then FPS rates drop after that. Is that entirely heat related? What about power? Even with the core at stock I'm still getting these results pauses when trying to overclock the RAM. I thought RAM just kind of went to its max and then stopped, and RAM sinks did close to jack (maybe 5MHz more, despite there being a huge hunk of aluminum on them now). I ran the numbers on my chips (K4J55323QF-GC20) and they seem to be 2.0ns models... great, screwed . I'm topping out at 1.13/1.14 before these pauses are starting. How did you guys know when to stop overclocking your RAM? What about cooling the MOSFETS? I'm just shooting observations out here and trying to get some feedback, I want to see how far you guys took your cards and maybe I can take mine there too

Thanks all!

 

[mentok1982]

I overclocked until I found that 3DMark05 stopped working after 435/1147.

 

[sam375]

I max at 1216. The RAM doesnt get much higher, nor should you worry about it too much, the core oc is much more important. Look at the 3DMark05 record holders, http://service.futuremark.com/compare?3dm05=700844 with the RAM at only 1300 with liquid nitrogen cooling. So you cant expect much more than 1200 out of the RAM with air.

 

[Mr. K6]

Wow, and this is with 2ns memory? What were your signs that 1216 was your max? I'm curious . mentok, I think 3dMark05 might have stopped working for you because of your 435 core, that's pretty high if you're using stock cooling

 

[sam375]

Wow, and this is with 2ns memory? What were your signs that 1216 was your max? I'm curious . mentok, I think 3dMark05 might have stopped working for you because of your 435 core, that's pretty high if you're using stock cooling

456/1216
Of course its detected low in 3DM05 as 1215. Detected as 1.22 in coolbits2 (they round up I guess) and 1216 rivatuner.

 

[Mr. K6]

ooo, 6K+ , but did it start pausing/stuttering when you tried to go for higher? Or did it give your typical texture missing flashes, etc.?

 

[sam375]

ooo, 6K+ , but did it start pausing/stuttering when you tried to go for higher? Or did it give your typical texture missing flashes, etc.?

Well, I havent exactly tried it any higher. As I said before, the core oc is much more important. 1Mhz core give about 10+ points in 3DMark05, 1Mhz mem almost nothing, about 2+ points if that. So thats why I dont worry about mem too much and focus on the core oc. I only worry about mem oc when Im really close to an even number. Like when my 9800 Pro was stuck at 59,850 in Aquamark3, all I needed was a few Mhz out of my RAM for 60k. I never got it past 60k cuz I bought my 6800 and stopped caring.

 

[Mr. K6]

Since parts for my custom 6800GT HS won't come in until the end of the week, I decided I'd investigate overclocking the RAM.

Oh I am going to focus on the core, but first I need much better cooling than stock. That's why I figured I'd start pushing the RAM for now, then that'd be one thing out of the way once I get my cooling in

 

[sam375]

Oh I am going to focus on the core, but first I need much better cooling than stock. That's why I figured I'd start pushing the RAM for now, then that'd be one thing out of the way once I get my cooling in

Its a waste of time right now because with better cooling the RAM oc will go up. Just wait for your new cooler, add some RAMsinks and autodetect; its simple as that. Eh, I cant blame you tho, sometimes I like to oc for no practical reason when Im board

 

[Mr. K6]

Well, I ordered a cheap, aluminum kingwin heatsink. I'll cut that into 8 pieces and alumina epoxy it on to the chips. With luck it'll help

 

[legcramp]

here's my 6800ultra weith 1.6ns ram overclock right here...1.12....o m g

 

[Mr. K6]

it's gotta be cooling then, those chips should do 1250, correct?

 

[legcramp]

they should do 1200 actually..but I am not anywhere near that...grrr and my temps are like very good hehe I load at 68 most the time in rivatuner hardware monitor...

 

[fiberoptik]

My gt buckles at anything over 420/1150 with an nv5 silencer. Im pretty sure I botched the instalation though as my temps seem to be high at stock. I might be able to squeeze another 50mhz out of the memory and 20 or 30 core. As far as knowing when enoughs enough. I get 2 to 3 second pauses in games that occur closer and closer together until I get a lock up.

 

[J-Mag]

All showed the same results, core too high, snoflakes, RAM too high, missing textures, flickering, etc. Now my GT in either case, when clocked past a point, just starts freezing, be it half-life 2 or 3dMark05.

Thanks all!

I was having problems with my gt overclocks even when way under the autodetect that coolbits sees. Autodetect was getting about 417 1090, however my system was crashing and freezing under graphic load at 400 1050. Finally I replaced my PSU and everything is awesome now. I can run 425 1150 without any crashing or freezing whatsoever. Granted I am using an SLI setup so my power draw is alot higher, but I would definately make sure you get a quality PSU ( I ended up purchaisng the PC Power and Cooling 510 SLI )

 

[Mr. K6]

I've got a 470watt Enermax Noisetaker (sig), it's damn good, especially with the dual 12v rails. I still think mine's heat. I'll have to wait for better cooling and see if that helps.