Quick question for Athlon overclockers

[Muad'Dib]

I was screwing around with my Athlon today and it works great at an fsb of 107. When I tried 110, it froze at the windows startup. Is this most likely a ram limitation or should I change the volatage? I have no idea what I'm talking about, so don't mind me.... Just let me know why it stops there.

I have a: Athlon 700 (.18)
MSI K7-PRO (110)
And 196 megs generic pc100 (possibly the problem?)

Worked well at 753 with 1.6 voltage and I haven't taken off the case or anything to do any phisical mods.

If this makes sense and you can answer, please do. If not let me know and I'll try to translate...

Dimitri

[Thundrchez]

Honestly, anythin in your system could be the limitation. Most likely your limitation is coming from the AMD 751 northbridge. It has enough margin of error that you can run at 107, but not quite enough for 110.

A lot of the ram that is coming out nowadays can easily do 110, but that was not true 1 year ago.

I thought that the core voltage of the Athlon 700 was 1.65V. I know that mine is, but my K7-700 is also one of the earlier 0.25u versions, where you most likely got a 0.18u version. They could have dropped the voltage down a bit with the 0.18u version.

Increasing the voltage will help make the transistors switch a little bit faster. However, when you are going < .25u, the transistor switch delay is becoming a less and less significant portion of the delay with the signals. Increasing the voltage will make it capable of faster speeds.

If you wanted to be really adventerous, you might want to get a gold finger device (GFD) that will let you change the cache multiplier and cpu multiplier. That way you could increase the CPU speed without overclocking everything else in the system. However, installing a GFD will void your warranty.

[Wombat]

Thunderchez is probably right about the north bridge. It might also be your L2 cache, but I doubt it (you're overclocking that as well).

Thunder:
I don't know about a GFD that allows you to change cache multiplayer. I've heard of one, but I don't believe it until I see it first.

[Thundrchez]

I haven't seen or played around with any GFDs myself. I'm probably misremembering something, but I thought for sure that they do let you play with the L2 cache multiplier.

The 700MHz Athlons still run with a 0.5 multiplier for the L2 cache, which means that the cache runs at 350MHz or so. If you drop the cache multiplier down to 0.4 or 0.333, you can usually bump up the CPU speed quite a bit. (350 / 0.4) = 875. You might could push it a little bit further and get 900MHz CPU with L2 cache mult of 0.4 running at 360MHz. Make sure you have that puppy cooled down really good if you go for it, though.

[Wombat]

I don't know if the pins that GFD's can reach are able to control the L2 multiplier. It's adjustable on my CPU, but that's because somebody went after it with a soldering iron. The solder points were pretty deep into the CPU.
There is software that can alter the multiplier, but this doesn't help overclocking that much -- if the CPU is clocked too high, you won't be able to POST.

[Thundrchez]

http://www.amdpower.com/north.html

OK, it looks like the L2 cache option is available with only a very few GFDs, but the one review linked above is for one that does have L2 cache adjustment as an option.

[Wombat]

Yep, I checked it out. You have to open up your Athlon, and remove two resistors. You can't just snap it on.

I guess this counts, but it's not a simple slide on job.