Overclocking 300A facts or fantasy

[Finless]

OK, this may get a little long winded but I need to understand a few things before I go buy.
1) What is the diff between the abit BH6 and the BX6-2? Which is best?
2) The big question!
I have read about the PII 300 SL2W8 and understand about the Deschutes core and the 4.4ns cache ram chips.

OK, a PII has a 512K cache running at 1/2 the processor speed right? i.e. a PII 450 cache is 255 mhz yes?

OK, I understand that the Celeron has 128k cache and that it runs at processor speed i.e. 300a cache is at 300 mhz right?. Is it also a deschutes core?

Next question. is the multiplier on a 300a x5 or x4.5? If it is x5, how do you guys get to 450 setting the FSB to 100? 5x100 = 500!

Now, here is the part that almost seems unbelievable to me. If a real PII 450 cache is running 225 mhz, and a celeron 300a is at 300, it is hard to believe that a 300 overclocked to 450 or 504 can happen. Is not the 300a's cache now running at 450 or 504?
I almost cant believe that a 4.4ns cache chip can handle that!

Maybe I aint figuring this out right. I can understand that the processor may be a real 450 (or something) clocked down by intel but the cache chips are what bothers me about this. The PII's cache is half the processor speed for this reason (max cache on a 450 is 225). Getting double that speed on the cache sounds almost unbelievable!

So now, If all of you had to do it from scratch and had a mid sized budget, which is best for overclocking a PII 300 or a celeron 300a.

Thanks,
Bob

[Roy]

1. The BX6 V2.0 combines the best of V1.0 and BH6, making both obsolete. BX6 V2.0 is unquestionably best.

2. I think the cache runs at 1/2 the bus speed. Makes more sense.

Celerons use the Mendocino core.

The 300a multiplier is 4.5 - 4.5x66.67=300. So 4.5x100=450 etc.

The SEL 66/100 selection on the Abit boards changes the L2's latency from 8 (Hi) to 3 (Lo). The Celeron running at 450 gets a better CPUmark99 number than a P-II 450. The reason remains an enigma.

There seem to be many more success stories with the C300a. You would save about $30 that could go into better ram (important), and have a lot of fun while waiting for the next generation.

If you like knowledge, check my post about Understanding SDRAM Timings and Latency

[Isos]

The cache on Celeron CPU are part of the cpu chip itself, unlike P2-450 that has 2 separate cache chips on the PCB. No official rating for the built in cache since they don't get tested separately. If Celeron passed 366, the built in cache is rated at 366 also. The separate cache chips on P2 are tested and rated.

Comparing P2-450 @450 & a stable Celeron 300a running @450: If you are running applications and benchmark that does not require huge amount of data all the time, you will notice that Celeron will have a slight advantage running such application. This is due to the fact that the Celeron access the data in the cache twice as fast as a P2-450 will access the same data from its cache. If the application requires a huge amount of data-most likely there will be a cache miss. That's where a P2 will have an advatage over the Celeron setup. Having 512kb cache means less cache missed.

BX6-2, although it cost more than BH6 offers additional functions & features - like more memory slots, ability to assign IRQ to your devices & more FSB range to choose from.

It's difficult to find a good source for P2-300 that can run @450 or higher. Most dealer that have this baby priced them high. Again, even Celeron 300a are getting harder to find. Good luck.

[This message has been edited by Isos (edited 02-11-99).]

[bighammer]

The best bet is to pick through the codes on the PII300 if they will let you.
Your looking for week 37 to 39.
Well, that is my experience, other people may be able to tell you other dates but Intel used the 4.5ns cache chips then, that I do know