OCing AM2 Sempron 3000

[vfrex]

Stock = 1600. At first, I had trouble getting it to boot stable at ~1750-1800. I couldn't figure out why, until I started playing around with ClockGen. I kept moving the PCI-E frequency down when I moved FSB up. So keeping PCI-E constant, I was able to move far beyond 1800.

I locked PCI-E in BIOS, and went back to clockgen. I am now at 2100, and ran SuperPi 1M in 43s.


edit> This is all at the stock voltage.

[werty316]

Good job so far but I think you can squeeze out 200MHz or even more than that as the Semprons have been known to be good OC'ing chips.

[vfrex]

I'm a complete and utter noob to this overclocking thing, so I'm not entirely sure of what is stopping me from going higher.

[werty316]

If anything I think its the HTT holding you back as at 2.1GHz your HTT would be at 262.5 and with a default HTT multiplier that is a HT of 1312.5GHz.

Basically you need good cooling and a good motherboard capable to work stably with a high HTT frequency.

I know you have an AM2 chip but overclocking is the same as a S754/S939 computer so here is a good overclocking guide.

http://www.short-media.com/review.php?r=300

[vfrex]

I think the mobo is decent, but, I haven't been able to figure out how to set a memory divider in bios.

I have the Asus M2N-E. If anyone is bored and wants to look through the manual's bios screenshots, maybe you'll see something that I haven't?


If anything I think its the HTT holding you back as at 2.1GHz your HTT would be at 262.5 and with a default HTT multiplier that is a HT of 1312.5GHz.

Basically you need good cooling and a good motherboard capable to work stably with a high HTT frequency.

I'm having trouble keeping this stuff straight. There is no effective way to run a HTT divider, right?

[GIBSON]

As far as I know you adjust the HTT multiplier all the way from 6 to 1 if i'm not mistaken. You're supposed to turn it down a bit when you're overclocking as lowering the HTT multiplier doesn't have much of a performance hit while it allows for much higher overclocks.

[werty316]

Actually the HT muliplier goes form 1 to 5.
I couldn't find any review for your board but try this:

Keep in mind if you don't know what you are doing in the BIOS I suggest you not to mess around with it.

For the Memory divder
Goto "Advanced", then goto "DRAM Configuration", Changing the "Memory Clock Frequency" is your memory divider and it should have options like "DDR2 800, DDR2 667, DDR2 533, etc".

For HT settings
Goto "Advanced", then goto "Chipset" I am not sure which setting it is but its either "MB to SB HT Frequency" or "CPU<->SB HT Speed". Basically for the HT multipier look for options "5x, 4x, 3x, 2x, or 1x"

[vfrex]

Ok, first strange thing. If I reboot the computer while the processor is overclocked at all, it will fail to post. Also, I tried bringing down my memory frequency. That didn't really do anything.

Also, I tried bringing down the HT multiplier briefly before setting the PCI-E lock. I'll try again now.

[werty316]

You only use a memory divider when your memory halts a CPUs from overclocking further.

Here is what I follow:
If the HTT/FSB equal or less than 250MHz use "4x" HT muliplier.
If the HTT/FSB is greater than 250MHz use "3x" HT muliplier.

[vfrex]

Ok, I dropped the ram to 667 and HTT multiplier to 4x. CPU multiplier is x8.

Stock clock is 200 x 8 = 1600mhz

Brought it to: 220 x 8 = 1760mhz

HTT = 220mhz
Memory = 352mhz

Where do I go from here?

[Assassin]

Well I can say that i've seen semprons get a 50% OC so keep trying. My friend has his at 2.4. Try dropping your memory down a bit, just find its sweet spot. I'm stuck on pc3200 ddr so i can't lend too much advice with what ddr2 can do.

[vfrex]

I've got prime95 running, and am bumping the rate up a bit every minute or two. Up to 272fsb, 272HTT, 436 ram, 2179clock.


Ok, I got an error in superpi at 2216. That generally means that I'd need more voltage, right?

[werty316]

SuperPI error means there is a ram error.

Drop the ram to "DDR2 533".
Decrease the HTT multiplier to "3x".

[vfrex]

Ram timings are already loose (5-5-5- 18 ), and I am using a ram divider of 667. I guess I could go lower on that ram divider, but I don't think it would make that much sense. I think the superpi error might have been a fluke. I kept raising FSB to 281, at which point Prime95 errored. I am bringing FSB back down to 275, and will run memtest for a few passes. Then I'll try Prime95 for a few hours.

Sound like a decent gameplan? Is there any point in dropping HTT lower and DDR divider down when I'm around a 35% overclock (possibly stable) already?

[werty316]

At 281 HTT don't for get to drop the HTT to "3x". You might have hit a wall since Prime95 gave you errors. Increasing the CPU voltage should help if you can't get past 281 HTT.

[vfrex]

Ahh, yikes. I'm getting a lot of memtest errors, even down at 274FSB. hmm. Maybe going with a lower memory divider would be a good idea?

[werty316]

Ahh, yikes. I'm getting a lot of memtest errors, even down at 274FSB. hmm. Maybe going with a lower memory divider would be a good idea?
Quick question, what is you ram rated at? for example 533, 667, or 800?
Try using the 533 ram divider.

Sound like a decent gameplan? Is there any point in dropping HTT lower and DDR divider down when I'm around a 35% overclock (possibly stable) already?

Not doing this will not let you overclock your CPU to a higher frequency.
If you don't have good overclocking memory that will hinder you CPUs overclock if you want a 1:1 ratio.
General rule is keep the HT at around 1000MHz or lower. Having it lower then 1000MHz has no effect on performance since the latency is so low.

[vfrex]

800. Should I drop the HTT multiplier and memory divider at the same time? That will basically let me push the CPU higher. Then I just have to hope that my processor can handle the higher frequencies.

[werty316]

800. Should I drop the HTT multiplier and memory divider at the same time? That will basically let me push the CPU higher. Then I just have to hope that my processor can handle the higher frequencies.
Yeah drop both at the same time and give it a try.

[vfrex]

2300, so far no errors 8)

Between 2300 at a lower memory and HTT speed, and 2100 at the previous settings, how would you determine which would give better "real world" results?

[werty316]

Pure speed is faster so the 2.3GHz would bench faster than 2.1GHz.

On another note are you sure you have DDR2-800 as I forgot that only X2 and FX chips support DDR2-800. A64 and Sempron suppports DDR2-667. I think your motherboard would downclock your memory to DDR2-667 so you wouldn't actually be using DDR2-667 as a ram divider hence you would have to use DDR2-533 ram divider.

[vfrex]

At default, the ram is running at 800.


edit> also, I'm cutting down my memory bandwith, right?

[vfrex]

What might it mean if the machine can't do a soft reboot when overclocked? It needs to have the reset or power button utilized to have a successful boot.

[GIBSON]

What might it mean if the machine can't do a soft reboot when overclocked? It needs to have the reset or power button utilized to have a successful boot.
Beats me, my grandfather had the same problem with his comp (non overclocked of course :lol:) It disappeared when I replaced his crashed disk and had to re-install xp though.

[werty316]

When you mean soft boot do you mean rebooting your computer when overclocked? That means your OC is unstable.

If your memory is not good for OC'ing use the DDR2-677 memory divider, since that is waht your CPU supports anyhow, and OC from there. Also you are using DDR2-800 memory so you should be able to OC as a high as you motherboard and CPU can take you since you aave a bit of memory headroom.

[vfrex]

Soft reboot as in I let the software OS reboot. I realize that the OC is unstable, I'm just not sure which component is being pushed too hard. I've been running at either the 677 or 533 divider.

[werty316]

So you OC using software like CLockGen and then reboot?

Tell you what reset all your settings and OC using the motherboard BIOS so there are less headaches.

Also I don't think this has been asked but maybe post your computer specs. Your board could be holding your OC back.

[vfrex]

I've tried both Clockgen and through BIOS. Same results.

Mobo is Asus M2N-E
Ram is Corsair XM2 6400
PSU is Antec NeoHE 430watt

[vfrex]

Ok, I did a bit of experimenting...

I started off with the ram set to 667, HTT multiplier to 4x, CPU freq bumped up to 237. I booted into Windows at 237 and ran superpi, then memtest for a while. After a number of successful memtest passes, I rebooted the system to check whether it would actually post without a hard reboot before beginning a long prime95 test. NEGATIVE, fell flat on its face.

So, I started moving down, first to 230, then to 225. 225 would successfully reboot, 230 would not. The highest stable frequency at which I can consistently reboot without locking up before posting is 227.

I dropped the HTT multiplier to 3x, and moved the cpu frequency up to 230. It continued to freeze during a soft reboot. Then, I moved HTT back up to 4x and ram down to 533. It wasn't stable in terms of rebooting at this settings either.

So now I'm confused. Although I didn't test every possible combination of HTT, memory frequency, and CPU frequency in the pertinent range, I think I covered my bases pretty well. Does that give any indication as to why I'm hitting a wall at 227? I remembered reading something about possibly hitting a wall because of SATA ports being unlocked:

-SATA in port 1 or 2? Move it to 3 or 4, as 1+2 are generally unlocked. This may have been resolved with the Nforce4, but I am not certain. A sign of this is a limit around 229mhz

That is from EclipseOC: http://eclipseoc.com/index.php?id=6,9,0,0,1,0

I do have my SATA drives plugged into ports 1 and 2, and the first sign of instability with the overclock IS at 228. But then, I have an nforce5. I guess that is easy enough to check.


edit> That didn't help either.

edit edit> now its locking at 227. meh.

final update of the night> I got it to reboot a few times without freezing at 225. I wish I could figure out what is causing the instability and if it is correctable. Otherwise, maybe I could use clockgen to set the clock to a decent level when I boot into Windows, and reset it to stock when the computer goes down for a shutdown or reboot.

[Kougar]

Okay, I felt bad about your plight after my recent extremely good fortune in the OCing department, so knowing nothing about overclocking anything AMD I googled a little, and found this (http://forums.anandtech.com/messageview.cfm?catid=29&threadid=1908388), the official Anandtech thread on this motherboard. ;) It isn't looking pretty, but a quick scan of the first page gave me an idea. Have you updated the BIOS to the most current, or tried any of the betas for it?

I've only read about AMD overclocking so I can't spot anything wrong with your setup. I really would guess the mainboard is holding you back right now after having read some of those posts. XtremeSystems has some threads on this mainboard as well http://www.xtremesystems.org/forums/search.php?searchid=1988474 (http://www.xtremesystems.org/forums/search.php?searchid=1988474)

[vfrex]

Yeah, I mean, the processor seems to hold up well. I figure it isn't the issue, since I can take it up to 2400+ without locking up (outside of the boot issue that is). The ram is rated for 800, so as long as I'm running a divider, that should be fine as well.

I probably don't know anything more about AMD overclocking than you at this point. Everything I know is from reading a couple of guides and my mindless wandering through the BIOS.

Anyway, I posted on the anandtech (Joined: 06/14/2003). Ironically, I probably joined there to ask about the issue with my last build.

[werty316]

One way to find out if its your board or CPU is to drop the CPU multiplier down to a very low setting(5x or so) as well as dropping to a lower ram divider(DDR2-400MHz or so) and setting the HTT to 2x or lower and just increase the HTT/FSB.

[vfrex]

CPU multiplier is locked.

[werty316]

CPU multiplier is locked.
You should be able to decrease the CPU multiplier.

[Kougar]

That is a new AM2 processor, I am pretty they allowed you to lower the CPU multiplier? Any Core 2 Duo with the right motherboard support will allow the user to lower the CPU multiplier down to "6", for 1.6ghz speedstep operation.

[vfrex]

Remember, this is basically the bottom of the AM2 budget line. If I compare screenshots of the BIOS from the manual to mine, the line where the multiplier option SHOULD be doesn't even exist. Also, this processor doesn't support CNQ.

[GIBSON]

Well, you might have to unlock it then. I know there are some motherboards who tend to leave out a few options unless you press a certain key. Nothing mentioned like that in the manual?

[Kougar]

Well, the CPU might have it, but the board would have to support it and that board doesn't appear to from the sound of things. :( That was my last idea, I don't think that board is capable of anything more...

Gibson, not with an ASUS Board. That would be Gigabyte's boards that need the CTRL+F1 to unlock the the good stuff. :)

[vfrex]

There are other people with this board having a similar issue (inability to soft boot once FSB hits the mid 220's). I'm not quite sure how many at this point, but I posted on the asus "tech support" forum and am trying to get people on the anandtech forums to report back to me as well.

[werty316]

See if you have the newest BIOS for that Asus board. That is weird why the CPU multiplier isn't there/greyed out.

[vfrex]

I have the latest, aside from a beta bios which doesn't appear to fix anything for those who have tried it.


btw, a bit of a performance test:

Total time for ripping and encoding a dvd (same dvd, same settings, only change is the clock speed)

1600mhz: 2 hours 15 minutes
2300mhz: 1 hour 32 minutes

I would say that is a tangible gain :p

[Kougar]

Tangible?? Well I suppose you might be able to notice that difference... :mrgreen:

[vfrex]

Hey, for $60 processor that didn't top 108F during the entire encoding process, I'm not complaining.

[Kougar]

Sorry vfrex, I was trying to be facetious... I'd completely agree, that really is a pretty noticeable difference. ;)

[vfrex]

I figured as much. I had to brag about the price and heat output one more time though, before I slam my motherboard into a brick wall.