PSU wattage and safety margins

[machine67891234]

CPU
219.99
Intel Core i5-3550 Ivy Bridge 3.3GHz (3.7GHz Turbo) LGA 1155 77W Quad-Core Desktop Processor Intel HD Graphics 2500 BX806237I53550
http://www.newegg.com/Product/Prod [...] 6819116505

Motherboard
79.99
ASRock B75 PRO3 LGA 1155 Intel B75 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard
http://www.newegg.com/Product/Prod [...] 6813157314

RAM
42.99
Patriot Gamer 2 Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model PGD38G1600ELK
http://www.newegg.com/Product/Prod [...] 6820220558

GPU
349.99
ASUS HD7870-DC2-2GD5 Radeon HD 7870 GHz Edition 2GB 256-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Prod [...] 6814121624

PSU
79.99
Antec EarthWatts EA-650 GREEN 650W ATX12V v2.3 SLI Ready CrossFire Certified 80 PLUS BRONZE Certified Active PFC Power Supply
http://www.newegg.com/Product/Prod [...] 6817371044

SSD
74.99
Mushkin Enhanced Chronos MKNSSDCR60GB 2.5" 60GB SATA III Asynchronous MLC Internal Solid State Drive (SSD)
http://www.newegg.com/Product/Prod [...] 6820226247

HDD
99.99
Western Digital Caviar Green WD10EARX 1TB IntelliPower 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive
http://www.newegg.com/Product/Prod [...] 6822136939

DVD-ROM
22.99
LITE-ON 24X DVD Writer 24X DVD+R 8X DVD+RW 12X DVD+R DL 24X DVD-R 6X DVD-RW 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM Black SATA Model iHAS424-98 LightScribe Support
http://www.newegg.com/Product/Prod [...] 6827106335

Case
79.99
Corsair Carbide Series 300R Black Steel / Plastic ATX Mid Tower Computer Case
http://www.newegg.com/Product/Prod [...] 6811139011



So for the build listed above, I have spec'd out a 650 watt PSU, which I think may be overkill. The newegg.com calculator doesn't provide estimates for the 7870HD GPU.... I ran some calculations in Excel using estimates from Scott Mueller's upgrading and repairing PC book and came out with a worst case number of 582 watts (I chose high for all estimates).

Couple of questions:
If the power supply is oversized and the components don't draw the full amount does it still waste power?

Is it ideal to have a smaller supply to the system?

Can someone describe the whole bronze, silver, gold, etc certifications?


Thanks for any input!

 

[machine67891234]

HIS IceQ Radeon HD 7870 $349 before $20 rebate and free shipping. About $28 savings over Asus model.

Also, regarding the case and the PSU - Is it better to have a top mounted PSU in the case? I would think this improves airflow and reduces dust getting into the fans (since it is not sitting on floor)

 

[WR2]

It's hard to quantify that. The same GPU and board components, course.
The differences would be in the fans/cooling arrangements and even those aren't much different.
HIS has a reputation for making quieter graphics cards.

 

[WR2]

I think you'd be hard pressed to find a modern gaming case with a top mounted PSU.

The heavy CPU in the bottom of case gives better stability.
And a bottom mounted PSU is often flipped so the intake is from inside the case and exhaust to the outside of the case. Minimizes dust issues.

 

[machine67891234]

It's hard to quantify that. The same GPU and board components, course.
The differences would be in the fans/cooling arrangements and even those aren't much different.
HIS has a reputation for making quieter graphics cards.

Yeah, true depending on the size and space I could always put the computer on the desk to minimize dust build up.

 

[Rugger]

Is Seasonic a better quality mfg. than Antec? By dropping down to the 520, would I still be operating in the middle third of the PSU range (to minimize heat and fan noise)? Factoring in 3.99 shipping, it's really only a $6 savings and I lose 130 w of capacity. That is why I ask about the quality of the mfg. comparison.

I doubt that your PC will pull more than 300W at load in real world usage. PCs use much less power than most people think. Take a look at this article on power consumption from 3 modern PCs at SPCR: http://www.silentpcreview.com/article1245-page1.html
They don't go over 400W until using an SLI config and a power hungry CPU. Your PC will use less power than the 2500K/6870 PC and it only used 271W at full load running Prime95/Furmark. nVidia and AMD already factor in sufficient extra power in their PSU recommendations to put total system usage in the PSU efficiency sweet spot of 40-70% load.

Antec is a great PSU mfr, but the S12II-520 is higher quality than the Antec EA-650D. The Seasonic is 80+ Bronze and has a 5 yr warranty while the EA-650 is 80+ and has a 3yr warranty.

 

[machine67891234]

CPU + Mobo combo
289.98
ASRock B75 PRO3 LGA 1155 Intel B75 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard bundled with
1x Intel Core i5-3550 Ivy Bridge 3.3GHz (3.7GHz Turbo)
http://www.newegg.com/Product/Comb [...] cvhvvq32ql

RAM
42.99
Patriot Gamer 2 Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model PGD38G1600ELK
http://www.newegg.com/Product/Prod [...] 6820220558

GPU
349.99
HIS IceQ H787Q2G2M Radeon HD 7870 GHz Edition 2GB 256-bit GDDR5 PCI Express 3.0 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Prod [...] 6814121624

PSU
79.99
Antec EarthWatts EA-650 GREEN 650W ATX12V v2.3 SLI Ready CrossFire Certified 80 PLUS BRONZE Certified Active PFC Power Supply
http://www.newegg.com/Product/Prod [...] 6817371044

SSD
74.99
Mushkin Enhanced Chronos MKNSSDCR60GB 2.5" 60GB SATA III Asynchronous MLC Internal Solid State Drive (SSD)
http://www.newegg.com/Product/Prod [...] 6820226247

HDD
99.99
Western Digital Caviar Green WD10EARX 1TB IntelliPower 64MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive
http://www.newegg.com/Product/Prod [...] 6822136939

DVD-ROM
22.99
LITE-ON 24X DVD Writer 24X DVD+R 8X DVD+RW 12X DVD+R DL 24X DVD-R 6X DVD-RW 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM Black SATA Model iHAS424-98 LightScribe Support
http://www.newegg.com/Product/Prod [...] 6827106335

Case
54.99
NZXT Tempest 210 CA-TP210-01 Black Steel / Plastic ATX Mid Tower Computer Case
http://www.newegg.com/Product/Prod [...] 6811146084

Total is 1015.91, however there are $30 in rebates, and free shipping on everything.

Final cost 985.91

Here's the updated build: The combo deal on the mobo and CPU shaved off $10, and the HIS IceQ 7870 had free shipping plus a $30 rebate. Also changed the case, I lost 1 USB 3.0 port on the front, but kept 1. Price was reduced by $25. Also decided to stick with the Antec PSU, because based on reviews they seem to be a pretty solid mfg.

Thanks for the link to the discounted 7870, WR!