P4 1.6A is like a fine wine....

[Beaner]

It just gets better and better with age!

Hey guys... I have been busy lately and haven't spent much "quality" time with the 'ol Northwood, so I figured I'd test her out again.
I have a P4B266-C and 1GB of Crucial PC2100.
I had been running at 2.3 Ghz, which was my max when I built the rig ~3 months ago.
This morning I was able to get her all the way up to 170 FSB (2.72 Ghz). Windows loaded at 2.9 Ghz, but Prime95 shut down.

Anyway, I have 2 questions:

1. I want to upgrade to a 512 stick of Corsair XMS and try using the 3:4 trick on the board. That would put my Ram somewhere around 453 mhz. What would be the best choice to make this happen? XMS 3000, 3200, or 3500?

2. When you reach the point in your overclock where you get random reboots or Prime95 errors, how do you determine wether it's your memory or your CPU holding you back?


Thanks for any help.

 

[Duvie]

Well I usually run my memory at the lowest ratio available and the lowest timings available until I find the cpu's limit....

The pc2100 may be a guess at the hold back in your system since it is 266mhz ddr and with 170fsb you would be running 340mhz....


I would run memtest and see if the memory errors out after I get an error in prime95 with your system....


For me my memory is rated 400mhz ddr so I would leave it at 1:1 ratio until I failed prime and then in that cas I was well assured it was the cpus true limit...then once I start tweaking memory it often may mean backing off a bit to get faster memory timins which can equate to better performance versus higher overall clock speed in some instanances.

 

[Beaner]

Thanks Duvie! Great info!

I suspected my RAM as well.
I also agree that higher memory bandwidth often yields better performance than higher CPU clock speed.
How would you go about determining the best trade-off point? Check Sandra scores?

 

[Duvie]

Test it in your most used real world apps....reason?? Some programs are more bandwidth hungry then others...

In my testing I found in cpu intensive programs like mp3 and divx encoding and autocadd generally 100mhz more of ddr was equivalent to about 70-80mhz of raw cpu power...

1.6@2.64ghz with 440mhz ddr cas 2.5,3,3,6 = 1.6@2.72ghz with 340mhz ddr.....cas 2,2,2,6


some of it obviously could be from the downgrading to cas 2.5 at 440mhz ddr so likely if I coul run cas 2 and more aggressive timings it could have taken 2.75ghz at 346mhz ddr to equal it...

Get some decent pc2700 ddr that can run cas 2 and you should be able to run 340mhz ddr with most aggressive timings and you will see a performance gain in just that as well have a little more headroom....In my opinion the pc2700 ddr and your nice 170fsb chip will fit just nicely in a dual ddr mobo coming out...you will be sittin very pretty with that chip!!! Don't sell it for awhile....

 

[fluxquantum]

i am also enthusiastic about running my P4 1.6A higher. i own an asus P4T-E flashed with the P4T533-C bios and it's overclocked to 2.3 as well. i just got my swiftech mcx4000 heatsink and the temps are great. in the future i will upgrade and try to see how far i can overclock.