I'm probably being stupid here.

[Mugz]

This isn't so much a question as a request for confirmation.

Pentium D 805 CPU. ECS PF5 Extreme motherboard. ATI X600XT 256MB. 2048MB RAM (4x Samsung 512MB DDR2-533 modules, 2 of which were formerly in my 'work' system).

Cooling is provided by a CoolerMaster Aquagate, 775 version. SpeedFan reports my CPU at 41ºC idle, ~50ºC load.

OS = XP Pro SP2.

The system is 48Hr Prime95 stable (when it boots into Windows).

Current CPU Speed: 3.0GHz from 2.66; FSB 150 from 133.
At 151 FSB the system doesn't even get past POST before flashing an 'OverClocking Failed' message.

I used to be able to hit ~3.5GHz easily, but my DDR2-667 RAM (2x Transcend 1GB) is now lurking in my E6600 'work' box.

My guess is it's the RAM.

Should I loosen timings and soldier on, or invest in a pair of 1GB DDR2-800 modules?

Bearing in mind, the system flies. I'm just an extremist.

Also, don't even bother with any C2D/C2Q suggestions. Physically, they will fit (LGA775). The board is not compatible though, and I'm considering a D 945 or 965 when the prices have dropped to ridiculous levels. I'm also not inclined to muck about with the 'work' PC. The RAM that was in there is currently in the D805 system (and doubled), and the D805's RAM is now with the E6600 - probably why AutoCAD/Rhino/3DSMax/etc all fly instead of crawl lately.

(I'm intending on getting a pair of DDR2-800 modules anyway, the real purpose of this post is to decide whether I get tires for the 'toy' this month and RAM next month or vice versa.)

Also, anybody tried OCing an ATI FireGL card yet?

 

[jeff_2087]

Your DDR2 533 should be easily able to run at up to 266MHz FSB if it's in sync mode. So maybe it's not in dual channel and it's running each separately at 600MHz (4x150)? In which case it'd be easily solved by running them in dual channel mode. There shouldn't be any need to get new RAM, that stuff is way faster than the system.

 

[Mugz]

Thanks for the input. My guess was the RAM due to it being of the el-cheapo variety.

Played around a bit last night, I can get up to 3.3GHz with 2 out of 4 512s in. It's permanently in dual-channel mode.