Not on an 8400, but on an XPS G4 with 3GB RAM - which is just a fancier version of the 8400 from the XPS line of gaming computers. Windows 7 installed with no additional drivers needed and has run like a dream for almost a year now. The only thing is the game port on the Audigy Z sound card is not supported by Windows 7 (but the sound card itself works fine), which was not a big deal for me. Since W7 will eat a GB just to stay alive, 2GB might be enough if you aren't doing any really memory-intensive stuff like hard-core gaming, video-editing, modeling, etc. My kids play Age of Mythology all the time and my wife is a photographer - she is its primary user, and rarely does she hit a wall at 3GB.
I'm running Win7 Home Premium on an 8400. It was OK with 2GB RAM and the original video card (Radeon x300) but not great.
I went to 4 GB RAM (of which ~3.5 are available in a 32 bit system) and added a GeForce 8400 GS video card and it's much better. I don't game so I can't tell you about that. It's great for TV and Netflix online driving a Dell 2707WFP monitor . Very snappy with Web and and Office applications. Aero is fully enabled and works great. It feels snappier and smoother than it did with XP.
Have you tried running the free Win 7 Upgrade Advisor from Microsoft? It isn't perfect but it's a good place to start.
XPS 8100 i7-860(8MB Cache, 2.8GHz), 8GB Dual Channel DDR3 SDRAM @ 1333MHz, 750GB SATA 3.0GB/s 16MB Cache, nVidia GeForce GTS2401GB GDDR3, Dell ST2310 Full HD Widescreen Monitor, AverMedia G2 Combo hybrid TV Tuner, dual 16x DVD+/- RW dbl layer, Microsoft LifeCam Cinema HD, Running Windows 7 Home Premium, 64 bit.
Yes, it will not only work, it will be awesome!! I just got mine installed on my 8400 with windows 7 64-bit about 4hrs ago and I can't believe I ever hesitated.
The way I did it was the very meaning of easy, and I kept my XP install just in case something went wrong, during my testing of 7 64-bit.
I will probaly erase it in a few days, but honestly if I knew it was so easy I would not have bothered. Well maybe I would have, just to be on the safe side.
It was no problem to get up and running and it only took about 20 mins to update.
The difference is night and day, not any solw down but indeed faster than before!
I can't even imangine what it would be like with 4 gb of RAM and a quility video card.
My windows score sucked, but ONLY because of my video card, which I am not joking when I say, is the worst PCI E card there is. Just look on e-bay there are at least 20 of them and NO bidders, lol! It is total garbage that is draging your whole system down if you still have it. Get a new one asap, even before more RAM.
That said, it runs so soomthly that I regret only that I waited to do this for so long.
Get the 64-bit if you can (you should be able to, but I don't know your exact specs)
My Dell 8400
I have a P4 HT 3.0
2GB of coursir RAM
925x SE chipset
ATI x300 video card (POS!!!!) LoL!!
I have a thread on TOM'S that I am going to update tomorrow detailing the steps I took, here is the link:
Please skip through the parts where people tried to hijack the thread and trade insults, just go to what should be the bottom and look for my tutorial.
I honestly don't know why people would get on the internet just insult people, its sad, just skip that part and read the TUT.
I really hope it will help you and save you the time that I spent.
This is a reply to your old post, but I intend to put a new HD in my 8400 and install Win 7 (32 bit). I don't seem to find your "step-by-step" instructions at your link to Tom's site. Can you still provide the info, or a link to same?
Follow my Windows Reinstallation Guide: