Hey there again, I think the heat wave here (20C+ counts as a Heatwave ) in the UK has befuddled my mind. I've just bought a laptop , however i ordered only 1GB RAM with it because it's cheaper to get more and fit it myself . Saving of £110 .
So then I'm going to upgrade the RAM to 2/4 GB not yet decided. Wouldn't 667 or 800 so-dimm be overkill or would the memory bandwidth still increase anyway? The reason I ask is because all 667/800 i can find is CAS 5 and 533 is CAS 4. Which would be quicker 800 CAS 5 or 533 CAS 4?
As i understand, the 533 supports an FSB of up to 266 so running it at 1:1 at CAS 4 would surely be quicker, wouldn't it? Anything higher .ie 667/800 would be a waste ?
Display: 15.4" WideXGA+ 1440 x 900 LCD (720p) with Clearview Technology Operating System: Genuine Windows® Vista Home Premium - English 32 Bit Graphics Processor : 512MB NVidia® GeForce™ Go 8800M GTX Processor: Intel® Core™ 2 Duo T9300 2.5GHz (6MB Cache 800MHz FSB) Memory: 1GB Dual Channel DDR2 SO-DIMM at 667MHz - 2 x 512MB CD/DVD/RW: 8x Dual Layer Writer (DVD±RW, CD-RW) Sound Hardware: Intel® High-Definition Audio (24-bit, 192Khz) with surround sound Wireless Network Card: Internal Intel® Wireless 4965 a/b/g/Draft-N Mini-Card
c - you're pretty much right, with the caveat that latencies are measured in terms of clock cycles, so CL4, for example, represents a different amount of time at 533, 667, and 800MHz. To figure out what's best for you, you'll have to do the calculation:
CL4 @ 533MHz: 4/533 = 0.0075
CL4 @ 667MHz: 4/667 = 0.0060
CL5 @ 800MHz: 5/800 = 0.00625
Thus, CL4 @ 667MHz should be faster than CL5 @800MHz.
However, there may be some slight latency penalties when not running the memory in sync with the FSB (in your case, not running at DDR2-400 or DDR2-800 memory bus speed), so I'd probably go with the DDR2-800 CL5.