T400 Processor Upgrade Advice

[msaddict]

Hi all,

I've a T400 with a P8600 and have been looking at upgrading it to give the old girl a new lease of life (in combination with an SSD and more RAM which I've already swapped from somewhere else). I'm looking at either a P9700 or T9900 but need some advice on which would be a better choice.

I'm not sure if the T400 ever shipped with a T9900 and I don't know how it's thermal 'dynamics' would be affected (if at all), likewise I'm also not sure if the lower TDP of the P9700 would give noticeable battery longevity in comparison with the T9900.

Advice on the matter would be much appreciated!

[richk]

T400 was shipped with all 3 CPUs you are talking about, so any will work. In general, any CPU upgrade is the least cost-effective upgrade for most users. Your SSD and memory are the first upgraded I would suggest. I run a T9600 CPU in my machine and do not have a heat problem, but the machine uses more power than a P8600 or a P9700, and more power certainly means more heat. If you look at the Intel specs, the "Thermal Design Power" of the P8600 is 25-watts, vs 28 or 35 for the P9700 and T9900. Battery usage is not a major concern for me because I mostly run plugged in. The T9900 will certainly use the battery faster. It has been my experience that buying the fastest processor of a given group is not cost efective, so you might not get good value by choosing a T9900 (sells about $240 on eBay) over a T9600 ($90) or a T9400 ($45), but if you use the machine for CPU-intensive tasks, you will notice the difference.