gpu/psu dell dimension 8400 upgrade

your PSU is a 350 watt. It has i think if i remember right 18amps on the +12 volt rail. I used to have a 8400 before I built my current system. So your limited alot on what you can get. The last GPU I had in my 8400 was the ATI x850xt. Not sure if any of the newer ones can go in due to the PSU not having enough to power most of them. You could try a lower end 8000 series by nvidia an 8400 or some such, but they are not very good. You can replace the PSU, but its kind of a hit and miss. Some times it works and some it does not. I have had to replace dell PSUs and so far all of the ones i have replaced do work. A friend of mine has had no luck replacing PSU on older dells, they blow out his MB.

I have an old 8400 too.

Dell PSU are pretty basic and not the quality normally recommended by people here for new builds. In addition, yours is several years old -a PSU's power goes down as the capacitors age - and probably beyond warranty. So it would be nice if you could upgrade. On the other hand, how long do you anticipate using this sysem and how much money do you want to put into it?

My 8400 has a Delta PSU - (while not a manufacturer of premium pc PSU's, they have been making car batteries and electrical systems for probably at least half a century so they know a little about it) with 17amps on 3.3v rail, 22amps on 5v, and 28 amps on 12v. This is good as it has more power on the 12v rail than most older 350w PSU.

Your system, with the minimal equipment you identifed, should be running at about 250w, So you have room to upgrade the video card as long as you don't get too carried away, and you have a PSU similar to mine. I am using a 6600GT on that PC (which has a tape drive and several PCI cards - apparently more than your system) which requires 48 watts of power at peak 3D use.

Looking at the new list just published today by THG -


Good choices would be a 9600GT which peaks at about 61w or the 8800 GT 512MB which peaks at about 78W. With the latter - your system would be about 298w ( 250w - 30w for current card + 78w for new card). This would put your system at about 85% of capacity - which is pushing it a little but should be workable. However I would be much more comfortable with the 9600GT.

Again the above is predicated at continuing with the current PSU when most would recommend upgrading just to get a better PSU even if there were not a power issue.

While THG is my favorite forum, youi might also want to go the the Dell forum which is actually quite active and you can search from what are numerous posts from other 8400 owners who dealt with PSU and video card upgrade issues.

There's no proprietary hardware in an 8400 that a standard ATX psu won't hook up to.
The stock psu has dual 18 amp rails with a combined output of up to 28 amps, I ran a 7900 GTO overclocked above GTX specs on mine.
Because of the added wire length and extra connectors the Corsairs would be a pain to install, something more basic like an Antec EA430 would have an easier time ( though you'll still have to cut the back panel).

Yea I think that the difficulty is deciding whether I want to spend the extra 75 to 100 bucks on the PSU given the age of the system. On the other hand, I purchased relatively high-end 4 years ago specifically so that I wouldn't have to upgrade while I was in college. Now that that's over, there is something to be said for just buying/building a new system rather than upgrading. Still, if I upgraded I think I would be in good shape for another two years, so waiting til then (at which point i would probably switch to a high-end mac) is probably my best bet.

At any rate thanks for the good advice so far.

I'd say get an 8800GS anything more your CPU will limit and even that your CPU will not allow it to perform to it's peak. Your PC is 4years old and that is an old man for a gaming machine. If you want to get a little more life out of it go for the 8800GS. However if all you are playing is WOW then you can get away with maybe an 8600GT or something. Your PSU won't take much more than the 8800GS though. I'd really consider saving it for a new PC though. You can always transfer the 8800GS to a new rig once you have the $$. But don't expect much from a video upgrade, you won't get the WOW factor. <-- and im not talking world of warcraft WOW on that one.

Mac? You're going to build your own Mac?

I am currently planning a new sysem in about two years, too, by which time I hope the following major improvements are available:

1. New Nehalem CPUs at reasonable prices
2. CPU harnessing GPU power for calculations
3. SDD at reasonable prices for an operating system only drive - say 128 GB
4. PCIe 2.0 in the mainstream at mainstream prices - mobo and GPU
5. DDR3 prices down to a reasonable level with faster chips
6. SATA 3.0
7. Vulcan mind-meld attachment to replace keyboard and mouse - also at reasonable prices

Mac's are good for Graphic Design, easy use, or trendy people. Take your pick, but I am removing "easy use" since you are posting on here and probably have some knowledge of computers. So that leaves Graphic Design or Trendy person. Which are you? hahaha

I know preople who are in Marketing and are Graphic Designers. Alot of them that aren't trendy have a Mac for work and PC for everything else.

I guess I am very untrendy since I have no Mac - neither work nor home. Actually I am a pre-Maccie. My first computer was an Apple IIe. $1750 and all I could do with it was word processing and play hang man. I upgraded after that to a faster Apple pc with a speedy 33Mgz processor. But then I made the switch to IBM clones with a Gateway G266 powerhourse.

Yeah but the apple II was HIGH TECH them and IBM really didnt catch on yet

02/24/2009 Response:

I have the same system you do with the following upgrade history.

1) 2 years ago, with standard 350 Watt PSU, upgraded from ATI X300 GPU to NVidia Geforce 7600GT GPU. No problems.
2) Got into more gaming, jumped RAM to 3 gigs. Great addition. No sense maxing out to 4 gigs, the 8400 will only recognize a max of 2.6 gigs. Added 1 gig sticks 240 pin DIMM, DDR2-PC2-5300, CL= 5, unbuffered from Crucial. This fixed the glitches I had when running MoHa. Also cleaned up a couple of small issues I had when running CoD4.
3) Recently wanted to upgrade GPU again, needed larger PSU. PC Power and Cooling has a line of Dell Compatible "silencer" PSU's that are direct mount up and plug in replacements for the standard PSU, went with their 500 watt PSU. PC Power has a nice table to verify PSU compatibility to specific Dell models. Once you get their part number, shop around. Found Amazon $20 cheaper and free shipping on PC Power and Cooling Dell compatible 500 watt unit. Following this upgrade installed a NVidea GeForce 9800GT GPU. This GPU is very smooth and runs fairly cool with integral cooling fan (right around 50 deg C).
4) Final upgrades (these are free once you've done your PSU upgrade and you may already have completed some of them).
a) In motherboard setup (on reboot be quick with the F2 key to get into it), scroll to the "hyperthreading" page (if you have the option on your system). See if your hyperthreading is turned on for your processor. Dell's default was "OFF" when they shipped 8400's, due to PSU limitations (350W). Turn on hypertheading. Save, exit motherboard setup and finish your bootup.
b) Bring up your task manager and where you may have been looking at one CPU graph under "performance" before, you should now be looking at two. Hyperthreading makes one processor function as two by looking for and using unused portions of the processor at any given point in time. You will effectively have two logical processors running at the same speed, (the closest thing to "dual core" you can be without actually having "dual core" hardware).
c) Right click on "my computer", click on "properties", then "advanced", then "settings" under "performance". Select "adjust for best performance", click "apply", click "ok", and do a restart to lock-in.

Switching on the hyperthreading and setting the system to "best performance" were the final fixes I needed to clean up running CoD WaW.

Why you chose to respond to an 8 month old thread I have no idea - but I am glad you did. I was surprised to learn from it that hyperthreading causes two graphs to show in the performance window of device manager. I have a Dell 8400 with HT and had always seen only one graph - and assumed this was normal since CPU did not have 2 cores. But I followed your suggestion and found that HT was turned off - so I turned it on and now have the 2 graphs. Thanks JNPBENT.
And now I am a little pissed at Dell. They advertised the computer as having a CPU with HT - and then they turn it off without telling their customers? What kind of deal is that? The setting even reported that the deafult was "off" - as indeed it was. I have been using my Dell for 4 years with HT turned off. I can't help but wonder why they did that - what they gained by the deception.
Even though it has been over 2 months since your post I am responding to bump it up in hopes that others might learn what Dell did and be able to fix it if so inclined.