How big a Power Supply for this sucker

[bg.graf]

I was helping a client who wants to build his own machine, this is what he's got (wants to put together). He thinks he can get away with a 500w power supply and I told him he should go with a 750w... Am I in the wrong here or do you all agree with me.

Qty. Product Description

1 MSI 870A-G54 (FX) AM3+ AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard

1 HIS H675F1GD Radeon HD 6750 1GB 128-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity

1 AMD FX-8120 Zambezi 3.1GHz Socket AM3+ 125W Eight-Core Desktop Processor
4 G.SKILL Ripjaws X Series 8GB 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory
2 SAMSUNG EcoGreen F4 HD204UI 2TB SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
1 LG Black Internal 12X Super Multi Blue with 3D Playback Blu-ray

 

[eric76]

I'd probably go with a 650 watt supply. Just built a computer last week and used this one. Very nice!

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139012

 

[16k_zx81]

I was helping a client who wants to build his own machine, this is what he's got (wants to put together). He thinks he can get away with a 500w power supply and I told him he should go with a 750w... Am I in the wrong here or do you all agree with me.

Qty. Product Description

1 MSI 870A-G54 (FX) AM3+ AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard

1 HIS H675F1GD Radeon HD 6750 1GB 128-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity

1 AMD FX-8120 Zambezi 3.1GHz Socket AM3+ 125W Eight-Core Desktop Processor
4 G.SKILL Ripjaws X Series 8GB 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory
2 SAMSUNG EcoGreen F4 HD204UI 2TB SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
1 LG Black Internal 12X Super Multi Blue with 3D Playback Blu-ray

The machine will pull well under 400watts

The only circumstance where a PSU bigger than 500W would be if he's adding a second video card. Even then power consumption would be under 500w, but you would want some headway in case he was adding any additional power-hungry devices.

 

[Cybjun]

Watt is not as important as what the amperage requirements are on the 12 rail. I personally like to use single rail power supplies like PC Power & Cooling 950w w/ 83A on 12V+, or the Thermaltake TR2 RX 750W which has 56A on 12V+.

side question from the specs you have listed this looks like a fairly high-end pc whats with the sata2 green drive. that will really hurt the overall system performance.

 

[bg.graf]

Watt is not as important as what the amperage requirements are on the 12 rail. I personally like to use single rail power supplies like PC Power & Cooling 950w w/ 83A on 12V+, or the Thermaltake TR2 RX 750W which has 56A on 12V+.

side question from the specs you have listed this looks like a fairly high-end pc whats with the sata2 green drive. that will really hurt the overall system performance.

I agree with you, He has a 7200 RPM 1 Tb hard drive already that he'll throw in as the main drive. I told him his performance will drop with the green drives but I guess he was looking for Capacity over price, and these are apparently much cheaper than the 7200 rpm.. If he doesn't mind the I/O speeds, well then good for him. If it were my pc I'd go with 7200 or 10k rpm disks.

 

[venist]

I agree with 16k a 500wt is more then enough for their needs. I only see a need for 600w or more if you add that second card, more drives and miscellaneous parts.

 

[tempusfugit]

On a side note, if he's gonna blow a bunch of money on a computer, can you talk him into spending it on good parts? Seems like he's just going for big numbers and not any testing.. amd 8 cores don't even outperform an i5, 32 gb RAM is overkill, especially with that weak 128 bit video card.

I'll bet for his purposes(obviously not gaming choosing that card), i5, 8gb RAM and an SSD will blow that set up away.

 

[OldSchoolPC]

On a side note, if he's gonna blow a bunch of money on a computer, can you talk him into spending it on good parts? Seems like he's just going for big numbers and not any testing.. amd 8 cores don't even outperform an i5, 32 gb RAM is overkill, especially with that weak 128 bit video card.

I'll bet for his purposes(obviously not gaming choosing that card), i5, 8gb RAM and an SSD will blow that set up away.

Yes, giving a client what they want isn't always giving a client what they ask for. But of course, if what they ask for isn't "bad" and it makes you more money then just do what they ask.

 

[sassenach]

What does he want the system for? The spec does not look very well balanced.

AS for power, AMD specify this for the GPU

450 Watt or greater power supply with one 75W 6-pin PCI Express® power connectors recommended (600 Watt and two 6-pin connectors for AMD CrossFireX™ technology in dual mode).

Cheap and/or badly spec'd PSUs are much more likely to be an early failure just waiting to happen.

 

[732914TECH]

i usually base the power supply on the video card requirements also

 

[phaZed]

So the here are the Top power numbers:
Radeon 6750 - 125Watts
MOBO - 100 Watts to be on the safe side (Just MOBO operation)
AMD FX-8120 - 95Watts
Samsung HDD - 7.3Watts
DVD/Blue Drive - ~30Watts

357.3 Watts total, and that is only when EVERYTHING is running on FULL at THE SAME TIME.

Run your Power supply at 75-80% capacity.. so 446Watts... or a 450Watt PS would be fine. 500 Would be my choice.

 

[hightechrex]

I was helping a client who wants to build his own machine, this is what he's got (wants to put together). He thinks he can get away with a 500w power supply and I told him he should go with a 750w... Am I in the wrong here or do you all agree with me.

Qty. Product Description

1 MSI 870A-G54 (FX) AM3+ AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard

1 HIS H675F1GD Radeon HD 6750 1GB 128-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity

1 AMD FX-8120 Zambezi 3.1GHz Socket AM3+ 125W Eight-Core Desktop Processor
4 G.SKILL Ripjaws X Series 8GB 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory
2 SAMSUNG EcoGreen F4 HD204UI 2TB SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
1 LG Black Internal 12X Super Multi Blue with 3D Playback Blu-ray

First off. Why would he get such a crappy card and then get a fx 8 core processor which has been proven slower than some of AMDs 4 core processor (single and multicore thread applications) and most of intel's.. even the i5s are faster. I suggest he save money; get a cheaper processor and a decent card i.e 6870 or 6950. Don't get me started on that 32 gbs of ram lol. 16gbs is fine.. most people will tell you that all you need is 8. But I actually did see an increase in performance from 8-16. Windows uses as much as ram as it can and takes what's left over and caches it. Plus 16gbs is going for 77-90 bucks.


Secondly, I think he'd be fine with a 500 watt PSU. Make sure its 80plus certified though.. If it isn't providing efficient power you may run into problems.

 

[Tony_Scarpelli]

I was helping a client who wants to build his own machine, this is what he's got (wants to put together). He thinks he can get away with a 500w power supply and I told him he should go with a 750w... Am I in the wrong here or do you all agree with me.

Qty. Product Description

1 MSI 870A-G54 (FX) AM3+ AMD 870 SATA 6Gb/s USB 3.0 ATX AMD Motherboard

1 HIS H675F1GD Radeon HD 6750 1GB 128-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity

1 AMD FX-8120 Zambezi 3.1GHz Socket AM3+ 125W Eight-Core Desktop Processor
4 G.SKILL Ripjaws X Series 8GB 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Desktop Memory
2 SAMSUNG EcoGreen F4 HD204UI 2TB SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive
1 LG Black Internal 12X Super Multi Blue with 3D Playback Blu-ray

I just bought a couple of i7 2600k's which are the 5 fastest cpu todate.
Both are different brands, one dell one Asus. Both have a 480W power supply. I guess it depends on the quality of the power supply.

 

[pc-quebec]

They are online PSU calculator like this one, don't forget to put a little more for capacitor aging

http://extreme.outervision.com/psucalculatorlite.jsp

those calculator are very generous, by experience, a PSU in real work draw far less than those estimate ( I always test my builds with a Watt meters betwen the PSU and the Outlet. )