TFX Power Supply

treebob · Post by **treebob** » Sat Apr 25, 2009 1:03 pm

I have run into a slight problem. I recently purchased a Dell Studio Slim computer. I love it but I wanted to upgrade the Video Card. Without thinking I bought a 9800 GT which needs a 400W power supply. Turns out that the Slim uses a TFX style power supply. The largest I have seen so far is 300W. Does anyone know of a larger power supply?

angelkiller · Post by **angelkiller** » Sat Apr 25, 2009 5:31 pm

I do not know of any TFX PSUs that are larger than 300W. TFX units are designed for slim systems and these types of system almost never have a high powered graphics card in them.

That said, a 9800GT only draws about 85W at load. So 300W is probably enough to run the system. You might want to have a look at this thread (especially the more recent posts) to get an idea of how much 300W can run. Assuming the PSU a quality unit, you could run a standard dual core CPU, motherboard, RAM, 1 hard drive an opticial drive and a 9800GT on 300W. However, the PSU in big-brand companies have been notorious for being of poor quality. This Seasonic unit seems to fit the bill nicely. Seasonic makes excellent PSUs, and I'd trust it to run a 9800GT system. Actually, I personally have that PSU. I have not tested it with a high powered graphics card, but I could give you measurements and such if needed.

Hope this helps.

treebob · Post by **treebob** » Sat Apr 25, 2009 9:48 pm

slight span, some rule about posting links

treebob · Post by **treebob** » Sat Apr 25, 2009 9:48 pm

treebob · Post by **treebob** » Sat Apr 25, 2009 9:48 pm

well it does help. I can tell you that it is this one. http://www.atxpowersupplies.com/250-Wat ... 250D5W.php

Not 300w but 250 (I have seen mention of 300W). I am running a Quad core Q8200 2.33MHZ CPU.

If you think that a 250W PSU is not adequate and I bought a good 300W SPU what should i look out for. For instance if it was not adequately handling the system will things noticeably malfunction int he computer?

angelkiller · Post by **angelkiller** » Sun Apr 26, 2009 6:49 am

treebob wrote:well it does help. I can tell you that it is this one. http://www.atxpowersupplies.com/250-Wat ... 250D5W.php

Not 300w but 250 (I have seen mention of 300W). I am running a Quad core Q8200 2.33MHZ CPU.

If you think that a 250W PSU is not adequate and I bought a good 300W SPU what should i look out for. For instance if it was not adequately handling the system will things noticeably malfunction int he computer?

Ok, I have some more data. Here is the power consumption of a q8200 system. Note that this is system-wide power consumption, most likely measured at the wall. If we assume the PSU was working at at least 80% efficiency (which is likely) then we get a power draw of ~165W for the Q8200 system at load. But realize that that system has a graphics card in it, a mighty 8800GTX. This link has the power consumption of an 8800GTX. Most importantly, the card idles at 70W. The 165W figure I obtained above was taken with the CPU at 100% usage and the graphics card at idle. So to get the power consumption of a Q8200 system at 100% load with no graphics card, simply subtract 70W. So our final system-wide power consumption is 95W. And of course this is an estimate, but I'd say it's within 10W in either direction. Finally, I'd like to add in your 9800GT to this number. From the link above, the 9800GT draws 35W on idle and 85W on load. So my estimated system power consumption of a Q8200 and a 9800GT is 120W on idle and 170W on load.

Sorry for the onslaught of data and estimation. But I wanted to give a number you could work with. I will admit that that 170W load figure does appear a little high, but I'm nearly certain, your load will be at least 150W. So this means that the PSU should be prepared to give 170W sustained. Running a 250W PSU would make me uncomfortable. There's only 80W to spare and the PSU would be running near 70%. While therotically, there is nothing wrong with this, as PSUs are rated by what they can give continiously. But in practice, many PSUs are often over rated. This is especially true for cheaper/low-quality PSUs. The Bestec PSU you linked to does not appear to be of great quality. I wouldn't feel comfortable stressing it at 70%. In your situation, I'd much rather have a quality 300W PSU. I mean quality as in, I know that the PSU is made of good parts and will deliver its rating without failing. Stressing a good 300W PSU at 170W is only running the PSU at 57%.

If a PSU is being overloaded, it should shut itself down to prevent damage. So you'll see lots of random shutdowns, especially when stressing the system.

Hopefully this wasn't too wordy or simplistic.

treebob · Post by **treebob** » Sun Apr 26, 2009 11:19 am

thanks for that, I understand it all so no problem. So as quality goes, do you have any recommendations on a 300W PSU that is TFX?

Riffer · Post by **Riffer** » Sun Apr 26, 2009 2:33 pm

treebob wrote:thanks for that, I understand it all so no problem. So as quality goes, do you have any recommendations on a 300W PSU that is TFX?

Someone above mentioned the Seasonic one.

Silverstone makes one that they put in their cases, but I don't know if it is available at retail.

Mats · Post by **Mats** » Sun Apr 26, 2009 3:15 pm

viewtopic.php?p=393849

angelkiller · Post by **angelkiller** » Mon Apr 27, 2009 8:47 am

I would feel comfortable with the Seasonic SS-300TFX. I actually have one and so far it meets my needs adaquately. Unfortunately, I haven't tested it with any high loads yet. (Only with an Athlon 3200+ system) I chose this PSU over other TFX models mostly because it was made by Seasonic. Judging by Seasonic's other PSUs, the SS-300TFX should be a quality unit. I found a few cheaper units by little-known brands, but after a few bad experiences I've had with cheaper parts, I now believe the saying, "you get what you pay for". And the PSU is an especially bad place to scrimp, as a failing PSU can potentially damage other components. Because of all this, I ponied up and paid for that Seasonic. As for the noise, I haven't heard it yet. That said, I haven't tried to either. I haven't noticed it over an AMD stock heatsink and a hard mounted 2 platter WD3200AAKS. So it should be fairly quiet, and not intrusive.

treebob · Post by **treebob** » Tue Sep 15, 2009 10:09 am

Hey all, update time.

I have the Dell Studio Slim with the 250W (stock) TFX PSU. I was going to buy a new 300W as this is as big as I could go but decided to try with out. I installed my low profile NVIDIA 9800GT and it hasn't had any power problems at all. In fact I love it! All my games play great with huge improvements. So looks like this is a win for me

Thanks for all the advice from earlier.