Present system (Sempron 2600+, Asus A7N8X-E deluxe) is now 3 years old and I'm looking for a cheap upgrade to something significantly nippier with better SATA support. Top of the shortlist Gigabyte P35-DS3L (£50) - don't need Raid or XFire, has all the connectors I want and the price is right. E2180 (£56.50) - hoping to get at least 3GHz. AC Freezer 7 Pro (£11.95). Might stretch to a Ninja but it's an extra £15+ 2x1Gb Corsair XMS2-6400 kit (£36.25) - 5-5-5-12 Question is on the memory. Is DDR2-800 overkill and is the £27 DDR2-633 cl4 a better buy? Or should I be looking at £52 DDR2-800 cl4? Hope is to oc to at least 3GHz on the cheap but stability is more important than speed, SOHO not gaming, probably stay with XP.
I built a Q6600 P5K System last week for me. I Upgraded from the same system as you (except mine was an AthlonXP 2600+) If you overclock to FSB1333 (3.015GHz @ x9) then theoretically you should still only need the 667 RAM (333 double pumped) but if you want to go any further without dropping below a 1:1 RAM:FSB ratio, you might need the 800. I got the 800 set, and am really pleased with it. Once I pop on an aftermarket cooler, I might consider overclocking more, but with the stock HSF, I'll stick to 3GHz.
If you can get a 667 kit for a decent amount less then any 800 kit(I don't really know what sites to look at in the UK for deals), go for it. With a processor of 10x multiplier, you can get up to 3.33GHz with DDR2-667.