A64 3000+ Overclocking Issues

[MrK6]

Hi, first post, long time reader :thumbsup:

Last month I built the system in my sig, it flies. Now that the summer heat has died down, I'm going to try some more extreme overclocking. When I first built it I boosted it to 266x8 (2.13GHz) so that my memory, which I'm told is the bottleneck of Athlon64 systems, would run at 213MHz and 2.5-3-3-8 timings. I've seen people get Athlong 64's to 2.5GHz and higher, I just will be happy at 2.4 (266x9). Couple of rules I'm following, dunno if I've been misled :frown:. I read somwhere that if you put your HTT bus at more than its rated speed, it'll go unstable. So, if you raise the HTT, you have to lower it's multiplier to keep it in specs, in this case, specs are for 800, so 266x3 is 798. What timings are other people using? I tired CAS2 RAM before and my A64 didn't like CAS 2 at higher than stock speeds. 2.5 seems to do the trick for now. Temps are good, I'm using a K8 silentboost all copper heatsink lapped to 1200 grit with a thermaltake 90mm CAT, 50CFM, fan on top of it. Idle is at case temp (29C atm) and load temps are 10 to 15C above that depending on the vcore. So, I guess I'm looking for some pointers or advice on what I'm doing wrong. I tried running it at 2.4 (266x9) with the RAM locked at 133 (171 actual) to make sure that's not the limiting factor. It gave me a rounding error after 9 minutes. I was using 1.65vcore, but it overvolts up to 1.72. Thanks for any help guys, it's much appreciated. Peace, Mr. K6

 

[Fern]

Welcome to the Forums!

I ddon't know, but here's a bump for you

 

[Quino]

Most likely is going to be the cooling. I had a 3200 and it would run at 2.4 for a while but then it would start giving me errors. I was using the same HS. I then switchef to the SLK948U and It was stable for a longer period of time. Finally I went with wattercolling and all my problems went away It might also be that ur motherboard hit a wall before the 266. I would lower the multiplier to like 4-5 and then try to go as high as you can to make sure is not the mobo. Usually when you really hit a wall windows would not even load Have fun and good luck. Really nce chips the A64

 

[zigzagzoom]

Is it a co or cg rev. cg seem to oc better. you can use cpu-z to check. epox has a utility to check voltage and temps get it to rule out heat. get latest bios from epox. when u flash bios watch your volts when i set mine to 1.55v it only showed 1.4v in epox utility. if it does do the jumper to reset bios, unplug it and take out battery. thenput it back together start it go to bios load optimized defaults. check volts then go play.

mine is at 2.4g (240x10) ,htt is 4x, mem divider 166 (5:4), memory running at 200 mhz (corsiar pc400 cl 2.5). if you something like clockgen in windows make sure to set cpu to 201 in bios and agp to 67 or the agp will be your limiting factor. i made this mistake. you may want to try something like 9x266 since you have pc 433 ram with htt 3x.

from what i have seen ram timing is not a big factor with the a64 because of the on die memory controller. so dont be afraid of cas 3.0 setting.

google is your friend. i spent 2 weeks reading forums and articles. heres a few links

http://www.aoaforums.com/forum/forumdisplay.php?f=27 epox forum

http://www.dugu9tweaks.net/guides/a64oc/index.html#intro oc guide
http://forums.pcper.com/showthread.php?t=299229 oc guide

http://www.ocforums.com/forumdisplay.php?f=1 good forum

im not an expert but hope this helps happy overclocking

 

[otispunkmeyer]

memory isnt the bottleneck on A64......the on chip memory controller was designed to remove that bottleneck

10-15% increase from single channle to dual channle on A64 platform simply isnt worth the extra $$$ as the memory controller is so good

 

[Jhatfie]

266 could totally be a wall for your motherboard, my old vnf3-250 topped out at 270-275. But, maybe it is something else since the Epox is usually a prettygood overclocker. I would also try your HTT multi at 2x just to see if it makes a difference. My VNF3-250 seems to dislike the 133mhz memory divider, but will run over 340 HTT with HT 3x with the 5:6 (166) memory divider. You may want to experiment in this regard some. I would do as Quino said and drop your multi using clockgen and up your HTT to see whhere your ceiling is in that respect. Then you can mess with your ram speed and timings. Cas is not that important to A64's like it is on P4's or XP's. ras/cas delay is more important than cas. You could also just be maxing your chip. Not all are good overclockers. I have an older CO 3000+ that will do 2.5ghz, but needs 1.76v to do it and my new 3200+ does well over 2.5ghz with much less voltage (currently at 2.56ghz 320x8 @1.6v), but is a newer CG newcastle.

 

[MrK6]

Wow, thanks for all the replies and info. CPU-Z says its revision SH7-CG, so I guess it should be a good overclocker then. I wish this board would have half multi's, as I could really use 8.5 right now. Basically, I'm just fooling around with settings. WHen I tried 266x9 I was at 1.65, and I got a rounding error, so that led me to believe it was the CPU causing the instability, but I can't believe it needs 1.7v to do 2.4GHz. What voltages are you guys using? I'm going to back down to 3-3-3-8 (as long as tRCD stays at 3, that's the biggest performance boost), and I'll trying using LDT of 4x, I must be missing out on a lot of HTT bandwith keeping it at 800Mhz. I'll try going up in htt in 1:1 with a 10x multi, seeing that it's working very well for you guys. See the thing is I'm trying to keep this at 1.55 to 1.6v for core, so if that keeps me at only 2.3, fine. I know 266 isn't a wall for me cause I'm running 266x8 right now, no hiccups, 30hours+ stability in prime95. My comp is close to silent (120mm and 92mm stealths) so I don't want to add a 948U and a tornado just to go a 100MHz higher. And yah, I followed that dugutweaks guide which lead me to believe to keep my HTT at 800MHz or under, guess that isn't true. It looks like a have some fooling around to do, but any pointers or discoveries you guys made are greatly appreciated. THanks for the replies, Mr. K6

 

[Quino]

The Nforce3 mobos unoffically (i believe) suport the 1000 htt I have my 3400 at 2.53 with 1.6 v but I am using watercooling. I am runing at a920 htt (4*230) and it is fast pretty fast Also, when i was using the 948U I was not using a tornado. I was using a pretty quiet thermaltake fan (maybe that is why it was still overheating heheheh) but it was as quiet if not more quiet than the K8 silentbust

 

[MrK6]

yah, I like the silence. I dunno, I just tried 220x10, all good. 225x10 I had to back off the RAM timings to 3-3-3-8, although I might just boost up the vdimm. I also had to boost the vcore to 1.6 to do 225, so I might see how far I can go at this setting. I don't want to go any higher for the sake of cooling (CPU loads at 48 but I think the mobo reads it a little hot). Thanks for the reply.