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View Full Version : OC'd AthlonXP w/400MHz FSB... Anybody got one?


Switch
08-22-02, 08:08 PM
I'm interested in the performance differences in a stock Athlon XP and an OC'd one using a 400MHz FSB... anyone out there using a system like this?

Renzo
08-22-02, 08:47 PM
I have results for similar increase, 50%

100*1,50 = 150 comparable to 133*1,50 = 200

System is:
Thoroughbred running at 1200MHz on KG7Lite
8*150MHz and 12*100MHz, 2-2-2 1cmd timings (fastest)
GF4 running at 306MHz/630MHz (this is not a vidcard test)
Resolution on games : 1024*768*32
MEM/FSB are running synchronously.

- Quake3 is version 1.31 and uses demo four, missing details : sky, dyn.lights, decalls, shadows

- Unreal is version 2.26b (gold) and has the latest OpenGL renderer installed. Missing details : fog

- Pifast calculating 4194304 decimals for the Pi with fastest options.

MEM/FSB ---- 8*150 ---- 12*100 ---- diff%

Pifast ------- 53,38 ----- 59,81 ---- 12%
Quake3 ------ 257 ------ 204 ------ 26%
Unreal ------- 142 ------ 121 ------ 17,4%

That should give some direction, if you're able to keep the same memorytimings. Faster processor might scale a bit more as it needs faster FSB than slower one (latencies get lower if you can use higher bus/lower multiplier).

StealthHawk
08-22-02, 09:36 PM
i think around a 350FSB is the fastest the Athlon can overclock to. unless someone has evidence of one reaching 400MHz FSB, i suppose it's possible with a super expensive cooling system like liquid nitrogen or something :p

Switch
08-22-02, 09:44 PM
This is pure speculation based on linear regression, and if my algebra is correct then a good guess based on your results would give:

Mult/FSB --- 6*200 ---- 8*150 ---- 9*133 ----- 12*100 ----diff%

Pifast ------- 47,81 ----- 53,38 ----- 55,85 ------ 59,81 ----- 10.4%
Quake3 ---- 310 -------- 257-------- 238 --------- 204 ------- 26%
Unreal ----- 163 -------- 142 -------- 134 --------- 121--------17.4%


I've added the 9*133 to show current FSB speeds... Also Renzo, are you sure you're %'s are correct for Pifast? I'm repeatedly getting 10.4 for that %. If anyone sees a problem with my math, feel free to comment.

It does seem as though a nice increase in speed would come from a jump to a 400MHz FSB... Epox has a good reputation for high FSB speeds.... though, I'm not sure what it'd take to get a board that high....

As far as Athlons overclocking to 400MHz. I've seen a review of the newest Epox board going that high with air cooling, I'll try to find it. I've also looked around VR-Zone (http://www.vr-zone.com/guides/AMD/TBred/) and as you can see 400Mhz isn't that uncommon, though most of those computers are cooled a bit to the extreme.

Renzo
08-23-02, 05:36 AM
I calculated the increases compared to slower numbers, so it is actually wrong as I divided by WRONG result :)

(59.81-53.38)/53.38 = 0.1204571

Should be:

(59.81-53.38)/59.81 = 0.107507106 = 10,75%

the difference 6,43 is 10,75% of the number 59,81.

59.81/(1/0.1075) = 6.429575
59.81*0.1075 = 6.429575

Few ways of confirming the result :)

In other way of saying this. I calculated the difference between the better and worse time, then I just calculated how many % is it from the weaker result, getting the gains compared to weaker result.

[edit: results]
MEM/FSB ---- 8*150 ---- 9*133 ---- 12*100

Pifast ------- 53,38 ----- 54.92 ---- 59,81
Quake3 ------ 257 ------ 244 ---- 204
Unreal ------- 142 ------ 137 ---- 121

I would run the test @ 7,5*160=1200 but my MB can't handle it (even if memory can handle 190MHz 2-2-5-2 1CMD).

What does this mean? Probably 1200MHz CPU getting all the data needed fast enough. I would test the cpu @ 1800MHz (18*100, 13,5*133 and 12*150) but KG7 doesn't boot up if I use multipliers higher than 13. CPU could run @ 2080MHz though.

Renzo
08-23-02, 06:55 AM
Originally posted by StealthHawk
i think around a 350FSB is the fastest the Athlon can overclock to. unless someone has evidence of one reaching 400MHz FSB, i suppose it's possible with a super expensive cooling system like liquid nitrogen or something :p
http://sivut.koti.soon.fi/macce/pics/2992.gif

CPU/watercooling, no mods to the motherboard.

Cotita
08-23-02, 02:33 PM
take a look at overclockers.com database, there are dozens of setups with 400+ fsb

StealthHawk
08-23-02, 09:27 PM
i stand corrected :o