Hi all, recently, i have decided to clock my 1.42 DP to 1.67 Ghz, exactly that same, like Andy from Bitsandpieces. With only one small difference: i wanted to do it with case closed. At 1.750 V there was no problem to boot my MDD, i only had to run my Delta AFB1212SHE at full speed (+53 dBA, loud as hell). Performance boost is quite well No crashes, no freezes. Temperature while Xbench test was 33 degs C, while Cinebench 2003 test there was 40 degs C (with Chud Tools and Aqua's Enable Nap script installed). I'm thinking, that 1.75 GHz is possible (at 1.750 V certainly not, it requires higher voltage, cause i had Kernel Panics at boot with 1.75 GHz), but i have no idea how to cool CPU and L3 chips (in my opinion, WC will be not enough, maybe Peltier + WC?). I have submit Xbench results to their comparison website, you may find it here: db.xbench.com/merge.xhtml?doc1=359219
After some tests, i think that 1.75 GHz with this CPU is impossible. I tried even 1.80 V - chime only, no boot. At 1.750 and 1.775 V machine trying to boot, but Kernel Panic occurs every time while system loading. It's not a matter of heat: i added second 120 mm fan, in place of optical drive carrier, connected to mobo - temperature while testing was 26-28 C (with case closed and optical drive door opened).
So we now know 1.67 is the max for the 7455. Congratulations on passing 100pts in Xbench Black! I am still at 1.5 with my machine. I messed with a ram disk for a bit myself, but was unlucky in getting it to work correctly. I will try again. Those drive scores you got from the ram disk are crazy fast!!! So whats next for you?
I'm having trouble duplicating your success with 1.67 I tried various voltages and never got anything stable. The closest I came was on my first attempt at 1.67 @ 1.75V. It ran for about 10-15 min. open case with the 120mm fan blowing directly on it then CP'd at 34.9C. Subsequent reboots CP'd during startup. I tried other voltage settings ranging from 1.65V – 1.8V. All CP'd at various stages of startup.
Currently running stable (so far) @ 1.58 and 1.65V. I'll take it but it's not as sexy s 1.67.