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A8N-SLI overclocking guide?

S

Speedo

Senior member
Even though I've done a lot of overclocking earlier, working with the A64 seems somewhat more complicated, with more variables.

For example, I'm wondering about settings like "Max Memclock", does this option let me play around with the FSB, and the memory will always be for example 400Mhz, no matter what?

Thanks
 
Anyone?

I know in the good old days, there were often specific guides out there, for specific motherboards. I could sure use a quick and dirty tweak guide for this mobo, since the manual isn't more helpful than the help descriptions next to the bios item...
 
Thanks RichardIII for bumping.

So far I've figured out that the "lock frequency" is just the memory divider, and shows the wrong speed when manually overclocking.

I set HT speed to 4x, memory speed to 333, and locked the memory timings (which also seem to go crazy at the auto setting). The 3000+ seems stable at 2.2Ghz, but I have one problem: Every time I reboot I get a halt, and an error message saying "an error occured last post" or similar, and I have to go into bios or press F1, even though it seemed to startup just fine. Right now I'm running some stability tests in windows, and so far it seems fine. Any ideas?
 
Here is a compilation of some of my postings

There are three main components overclocking, and you need to start out by testing each one seperately to find your limitations for each one.

1. Chipset (HTT bus speed) - To find your maximun HTT, drop your LDT to 3x, drop the CPU multi to 6 or 7, set max ramclock to DDR200. Then increase your HTT in increments as far as you can and remain stable (test with Prime95 for 10min). I can get to HTT 335, the best I,ve seen is 342

2. CPU - change the CPU multi to 9-10(test both), Increase the vcore to 1.550, leave the rest of the settings as described above. Now increase HTT as described above until you reach your stability limit. My best CPU overclock with the 3200+ on this board is 9x289=2601mhz.

3. Ram - Drop the CPU multi back to 6 or 7, and reduce to stock CPU volts. Change the Max Ram clock to DDR400 and increase DDR volts to the warranty limit of you ram. Set your timings at 3-4-4-10 1T, now increase your HTT as described above, except now use memtest to test for stability instead of Prime95. This board currently limits ram at 240-250mhz 1T. So if you've got the same ram as mine, you can skip this step because it will run 240-250 with auto timings at 2.80v no problem.

Once you go through these testing steps you will be able to identify your limitations in each area, You go with you maximum CPU overclock and set your max memory clock to acheive you best combined overclock


First off, Google for and find the free download for "Glockgen NF4" its a great tool for showing your CPU and memory speeds, and most importantly it will let you set the CPU voltage higher than the some bios.
1003.6 beta bios also supports a higher voltage setting

The bios voltages works this way

1.650 gives you 1.58 per cpuz and AI booster and Asus Probe
1.6375 gives you 1.58
1.550-1.6275 give you 1.50 (max setting in the 1003 bios)

Clockgen settings

1.550 gives you 1.58 (clockgen shows 1.45?)
1.450 gives you 1.58 (clockgen shows 1.45)

?Max memory clock? Is actually your CPU to RAM ratios (it does not limit ram to the rated speed) this confuses almost everone.

DDR400 = 1:1 ie? HTT 200mhz = Ram 200mhz
DDR333= 6:5 HTT 300mhz = RAM 250mhz
DDR266= 3:2 HTT 300mhz=RAM 200mhz
AUTO= auto dividers once ram reaches 217mhz and keeps it less than 200mhz



Start of by using the DDR266 setting 3:2 divider to remove ram limitations when testing for your best CPU overclock. Once you find the ceiling on you CPU you can adjust your RAM settings later. Leave all other ram settings at auto

Increase the CPU voltage to 1.550 in bios (1.50 actual), Change the HTT multi to 3x
Cpu muti 9
HTT 235
This will give you 2115mhz

From here increase the HTT 2-3 mhz at a time, test for stability with Prime95 or Super PI for 10-15 minutes every so often. When you start getting errors in Prime or Super PI use clockgen to increase the voltage to 1.550 (1.58 actual) continue increasing HTT until you get errors again. Back up to your previous settings (this is your maximum CPU O/C)


Check for the mfg's specs for voltage on your ram. I use OCZ and this board sets my DDR volts too low at default. My OCZ EL PC3200 Platinum rev2 call for 2.75 and the board gives them 2.60. I'm currently running at 2.80v 236mhz


 
Well I used this one http://forums.anandtech.com/messageview.aspx?catid=28&threadid=1497607 "Quick and dirty A64 clocking guide" over the weekend and am running my A64 3000+ @ 2430 (9x270) with just a little room. (Many thanks to Zebo for demystifying OC'ing)

Here's what my settings are
BIOS=1002 (my pci lock works as documented)
FSB = 270
CPU Multipier = 9x
HTT = 3x
vCore = 1.50V
DIMM = 2.85V
Memory locked at 333Mhz
CAS = 2.5
RAS to CAS = 3
Row Precharge = 3
Min RAS cycle = 6
So I guess that's 2.5-3-3-6

Have run benchmarks, game demos, prime95, superpi all without error. System runs about 32C with no load and gets to about 49C running prime95.

I'm sure I could push the system a bit more but very happy with the results so far. Biggest issue I have is Betty Bios complains "system failed due to CPU overclocking" about every other POST but I just hit F1 and everything is fine. I do leave the FSB set to a nice round 250 (instead of max 270) and plan to push it up only when doing heavy lifting like video rendering.

Some thoughts/notes
1) I maxed CPU out at just over 2.6Ghz. Actually I got nervous when FSB exceeded 300 and I chickened out.
2) My memory Corsair 3200 512C2-PT seems to be the weak link. If I run with < 2.85V I when trying to OC the system is really unstable.
3) I keep meaning to try a HTT 4x but not sure how it will behave. Found with everything set to AUTO I could only push FSB to 230 before system flaked out. So I am not it can do much more that 1000. That said I am running at only 810 when maxed (3x270).


BTW, I am a total noob and make no claims that I know what I am doing, just telling my results. Here's hoping I am not buring up my components.


John

 
Thanks GuitarDaddy! Your info was really useful!

However, I have the same problem as swindelljd. This system I've just built for my friend, is only overclocked midly. (I will build my own system soon and overclock to the limits). However, this system seems stable at 2.2Ghz (ran 3DMark all night), but still it shows this error message during post. How do I get around this? Is this a problem with only some BIOSes, or even some particular mobos?

Also, swindelljd, I think that when you press "F1" it will load up at default speed. This system was down to 1.8GHz, after I pressed F1. You have to enter BIOS and save, to keep running at the overclocked speed. Very annoying! If this can't be solved, I have to give it to my friend non-overclocked, even though it seems rock-stable at this speed. I will also be very dissapointed if the same problem occurs with my own system I'll be building in the coming week...
 
I think it is a bios issue. I'm using 1003.006 and I never get that message. When I tried 1004.001 bios, I immediately started getting this message. I haven't tried the 1003 release bios
 
Originally posted by: Speedo
...
Also, swindelljd, I think that when you press "F1" it will load up at default speed. This system was down to 1.8GHz, after I pressed F1. You have to enter BIOS and save, to keep running at the overclocked speed....
Click to expand...

Wow I didn't even notice that! I told you I was a noob.

I did find that it happens on cold boots. If I hit reset instead of F1 it does load the OC settings. Resetting does the same thing I guess as saving the BIOS settings but is a little faster and is a "wife friendly" solution 🙂

John
 
Hej swindelljd! Post error problem solved after updating to bios 1003!

Thanks GuitarDaddy for your help... Everything is running just fine now, and I also sucessfully replaced the chipset fan with a Zalman NB47, with a Zalman 80mm fan blowing towards it at low/silent mode. 255FSB all night long, no problem (haven't tried higher).
 
Speaking of "betty" she won't talk to me. I have the boot into os option turned on but I don't get any messgae. Is it because I am not using the onboard audio? I have it disabled because I'm using a seperate sound card. If this is the reason, is there any way to make the post reporter work?
 
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