I think the only significant upgrades in the TX5 are 2gb memory & (slightly) faster CPU.
I am using Vista (Home Premium) with my TX3 XP/L (1.5gb ram) and I am finding it as responsive as XP, even with Aero enabled. I suppose it depends what applications you are running also as to how responsive you find it.
My screen has always been fantastic, although I understand there are some TX owners with issues, but this has been the best screen I have ever used, and have never had any issues with it.
Fan noise - I’m sure will be the same wth the TX 5. You cannot really suppress the sound of such a small case fan unfortunately, and I doubt there is any space to include a larger one! Maybe the fan is a little more active with Vista, but if you turn off the Aero effects (most will after a while, I’m sure), it’s a little less prone to spinning up. Basically you will experience fan noise with he TX 5, it is inevitable.
As I type this my CPU uage is at 18-43%, with 40% RAM being allocated.
From standby, start up is max 5 seconds. Vista’s ‘hybrid sleep’ is also a cool feature, which combines the best of sleep and hybernation (rapid resume, slightly slower to go into standby mode.)
I regularly have multiple Fireworks/Photoshop windows open on top of Dreamweaver, and only experience slowdown when tryng to unrar large newsgroup dowloads whilt also trying to work (to be expected really)
Whilst I’d also like a white TX (for a change , the lid on the TX3 XP/L is still magical - in direct sunlight it glitters blue, at other times its slate grey - it’s an awesome feature, and extremely understated. Light leakage has also never been an issue withmy day to day working.
In all, I wouldn’t upgrade my TX3 for a TX5, and I’d still consider a cheaper, maybe second hand TX3 as an alternative to a TX5 if one was available - and no I’m not hinting at selling mine, I’m delighted with it!