Personal computing discussed

Moderators: renee, SpotTheCat, Nemesis

 
leftyassassin
Gerbil
Topic Author
Posts: 67
Joined: Wed Jun 16, 2004 2:57 pm
Location: Peoria, Arizona
Contact:

Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 1:19 pm

I'll be brief: I recently built a living room gaming PC after six years away from the hobby. I did not get a discrete GPU because I wanted to wait to see what Nvidia would do with Kepler in the $150-250 range. Now I'm thinking I might just go ahead with AMD.

So here's my build:
Antec High Current Gamer Series 400W (the modular version)
MSI Z77A-G45
i5-3570k
G.Skill Sniper DDR3 1600 (2x4gb)
Samsung 830 128gb
Kuhler 620 (with two fans in a push/pull)
Plus three additional low RPM 120mm case fans.

I'm looking at either a Radeon HD 7770 or a 7850 but my question is, can this build handle a 7850? I can do some quick math and say even with a 7850, under reasonable load, this system should not pull more than 300 watts, but I'm no expert and it's been a long time since I built a PC. I'm worried there are factors I'm failing to consider.

If someone could weigh in on this I sure would appreciate it.
 
EsotericLord
Gerbil First Class
Posts: 136
Joined: Mon Jan 11, 2010 1:23 pm

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 1:37 pm

Per AMD's website:
"500W (or greater) power supply with one 75W 6-pin PCI Express power connector recommended "

Not to say it's guaranteed to not work on a 400 watt power supply, but I really wouldn't recommend it.

http://www.amd.com/us/products/desktop/ ... 50.aspx#/2
 
BobbinThreadbare
Graphmaster Gerbil
Posts: 1195
Joined: Sun Mar 20, 2005 2:47 am
Location: Champaign, IL
Contact:

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 1:44 pm

According to TR, a 7850 with an i5 and some other stuff uses 172 watts under load.

http://techreport.com/articles.x/22705/7

So I think you should be fine, if you have enough power on the 12v line.

AMD's website vastly over estimates how much you need for a variety of reasons. There are a lot of crappy PSU's that don't deliver anything close to what they're rated at (Antec doesn't make the best PSU's, but they're OK) would be the biggest one.
 
Mentawl
Gerbil Elite
Posts: 504
Joined: Sun Dec 26, 2004 5:21 pm
Location: UK

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 2:06 pm

Yeah, you should be fine, Antec PSUs are pretty decent.

AMD's website has to account for the fact that some "500w" PSUs should be sold as "200w, maybe" supplies. The quality of some 500w supplies is truly dire.
i7-8700k @ 4.7ghz | MSI Krait Z370 Gaming | nVidia GTX1080 | 16gb DDR4 3200 | 2x SSDs 1x HDD | Antec Solo II | Dell U2713HM
 
EsotericLord
Gerbil First Class
Posts: 136
Joined: Mon Jan 11, 2010 1:23 pm

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 2:35 pm

Welp, I stand corrected.

/sheepish
 
Philldoe
Grand Gerbil Poohbah
Posts: 3045
Joined: Thu May 13, 2004 12:12 pm
Location: Turn around...

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 3:01 pm

Should be alright, but I would never chance it. a 500w PSU can be had pretty cheap from the egg.
Fastfreak39: I feel like they should change the phrase "jumping on the band wagon" to "sailing on the pirate ship"
 
moresmarterthanspock
Gerbil First Class
Posts: 108
Joined: Wed Jan 25, 2012 5:50 pm
Location: Podunk, Idaho
Contact:

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 3:21 pm

I usually go overkill on the PSU. I'm runnin a 700W in a system that probably only pushes 400W max. For one, it gives me the warm fuzzies, and second, it leaves plenty of room for upgrading and adding stuff later.
Change sucks
 
MrJP
Gerbil Elite
Posts: 836
Joined: Wed Nov 20, 2002 5:04 pm
Location: Surrey, UK

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 3:26 pm

You'll be fine with a reasonable brand like Antec. The 172W in TR's review is power draw at the wall, so if you assume the PSU used for the test is 85% efficient, the power draw from the PSU is only around 150W. Your PSU can manage 360W (30A) on the +12V rail which accounts for most of the power usage (CPU & GPU both use 12V), so you'll have at least 100% margin.

AMD's PSU recommendations are to cover people with cheap no-name PSUs with over-inflated ratings. For example, here's a cheap 500W PSU on Newegg that actually only offers 204W (17A) on the +12V rail. The rest of the "500W" is made up with unnecessary 15A ratings on the +3.3V and +5V rails. If you had this, you really would be chancing it with a 7850 in your system.

There's a lot more to PSUs than the headline rating.
i7-6700K ~ Asus Z170I Pro Gaming ~ 16GB Corsair DDR4-2400 ~ Radeon R9 Nano
Noctua NHU9S ~ Corsair Obsidian 250D ~ Corsair RM650X ~ Crucial MX100 512GB
SMSL M3 ~ Sennheiser HD555 ~ Logitech G500S/G910/G29 ~ LG 34UC79G
 
Chrispy_
Maximum Gerbil
Posts: 4670
Joined: Fri Apr 09, 2004 3:49 pm
Location: Europe, most frequently London.

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 5:06 pm

You'll be absolutely fine. Here's the furthest I've ever pushed an Antec PSU:

A four-year-old, dusty Antec 380W psu, it was one of Antec's cheaper units that they gave away with cases for next to nothing (i.e. the case with the PSU was price-competetive with similar cases sans PSU)
Anyway, at some point after digging it out of the parts box, it ended up powering an overclocked Core2 Quad (95W at least) and an 8800 GTX (155W spec). More than a few splitters/adapters were used by the time I was done, because the machine also had three hard drives, three 120mm fans, an SSD, a DVD drive, a seperate soundcard, wireless-G card and (as the cherry on top) a pair of XBox360 controllers.

It's probably not good to run a PSU at full load, but somewhere around half load is what you should aim for. Your 77W cpu and 130W 7850 wil probably push your system's total peak TDP up to around 275W, but peak TDP is really is rare these days. When the GPU is at full load, the CPU will likely be running cool, waiting for it to finish frames. When the CPU is running flat out, the graphics card probably isn't even running a 3D application these days. I bet you could run your 7850 system off a 250W FlexATX Pico PSU (from a decent brand at least), not that I'd recommend it, of course ;)
Congratulations, you've noticed that this year's signature is based on outdated internet memes; CLICK HERE NOW to experience this unforgettable phenomenon. This sentence is just filler and as irrelevant as my signature.
 
ultima_trev
Gerbil XP
Posts: 363
Joined: Sat Mar 27, 2010 11:14 am
Contact:

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 09, 2012 5:50 pm

I have an HD 7850 OCed to 1GHz and Core i7 970 fed by a 350W PSU, so 400 should be adequate.
Ryzen 7 1800X - Corsair H60i - GA AB350 Gaming - 32GB DDR4 2933 at 16,16,16,36 - GTX 1080 at 1924 / 5264 (undervolted) - 250GB WD Blue SSD - 2TB Toshiba 7200rpm HDD
 
JustAnEngineer
Gerbil God
Posts: 19673
Joined: Sat Jan 26, 2002 7:00 pm
Location: The Heart of Dixie

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Wed Jul 11, 2012 8:35 pm

Your existing power supply is fine for the Radeon HD7850. MrJP's response is spot-on.
· R7-5800X, Liquid Freezer II 280, RoG Strix X570-E, 64GiB PC4-28800, Suprim Liquid RTX4090, 2TB SX8200Pro +4TB S860 +NAS, Define 7 Compact, Super Flower SF-1000F14TP, S3220DGF +32UD99, FC900R OE, DeathAdder2
 
leftyassassin
Gerbil
Topic Author
Posts: 67
Joined: Wed Jun 16, 2004 2:57 pm
Location: Peoria, Arizona
Contact:

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Tue Jul 17, 2012 11:30 am

Thanks everyone for the insight. It sounds like a 7850 will be no problem at all.

Just out of curiosity, though... what about a 7870? A 7950? A GTX 670? Would any of those be feasible?
 
Chrispy_
Maximum Gerbil
Posts: 4670
Joined: Fri Apr 09, 2004 3:49 pm
Location: Europe, most frequently London.

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Tue Jul 17, 2012 1:19 pm

leftyassassin wrote:
Thanks everyone for the insight. It sounds like a 7850 will be no problem at all.

Just out of curiosity, though... what about a 7870? A 7950? A GTX 670? Would any of those be feasible?


It míght work, but I'd strongly advise against it, your PSU has only one PCI-express power lead. You might get away with adapters off the molex connectors, but I wouldn't advise it unless your machine has almost no other hardware in it; You have only a single 12V rail in your PSU and although it's a good 30A rail, a CPU and two PCI-E connectors is a lot to ask of it - expect hot & noisy if you do run a second 6-pin PCI-e connector off it using adapters.

For reference, these are the power and socket configurations of the cards you've asked about. 7850 would be the sensible place to stop, but if you are going to risk it, a GTX 670 is probably your best bet. It can draw MORE than the 7870 in things like Furmark and OCCT but most benchmarks using game tests show it pulling 15-20W less than a 7870 from the wall.

7770 = 80W peak (1x 6-pin power)
7850 = 130W peak (1x 6-pin power)

7870 = 175W peak (2x 6-pin power)
79xx = 230W peak (1x 8-pin + 1x 6-pin power)
670 = 170W peak (2x 6-pin power)
680 = 195W peak (2x 6-pin power)
Congratulations, you've noticed that this year's signature is based on outdated internet memes; CLICK HERE NOW to experience this unforgettable phenomenon. This sentence is just filler and as irrelevant as my signature.
 
jthh
Gerbil In Training
Posts: 9
Joined: Fri Sep 18, 2009 12:57 pm

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Tue Jul 17, 2012 5:24 pm

This website tool has been a favorite of mine whilst planning my new build(s).

It allows you to put ALL sorts of data into it and is regularly updated with the latest processors and graphics cards.

Enjoy!!
8)
http://extreme.outervision.com/psucalculatorlite.jsp
 
Geforcefly
Gerbil In Training
Posts: 3
Joined: Sat Jan 29, 2011 11:02 pm

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Tue Jul 17, 2012 6:49 pm

You've got some breathing room. I'm rocking an i7-2600K @ 4GHz, 8GB RAM, and a GTX 680 on an Enermax Liberty Eco 400W PSU with no issues at all.
DT: i7-2600K @ 4.0GHz, msi P67A-C43, 8GB DDR3-1600, WD Blue 1TB, Crucial C300 128GB, GTX 680, Win7 Home Prem. 64-bit
LT: HP Compaq Presario V5015US: Turion TL-32, 1GB DDR, 160GB HDD, WinXP
 
continuum
Gerbil Team Leader
Posts: 237
Joined: Mon Jun 09, 2003 1:42 am
Location: California

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 23, 2012 8:43 pm

You should be fine. I ran a Radeon HD 4870 (160W TDP) and a Core 2 Quad for extended periods in FurMark and Prime95 off an Antec Earthwatts 380W, and peak use was only 220W or 250W from the wall (something like that), well under PSU capacity. :)
 
zzz
Gerbil
Posts: 69
Joined: Wed Feb 16, 2011 6:19 pm

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 23, 2012 10:11 pm

It should work, you bought a decent PSU
 
Cyco-Dude
Gerbil First Class
Posts: 130
Joined: Sun Jul 13, 2008 5:45 am

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 23, 2012 10:27 pm

if you are unsure just look at tr's reviews, and see what their test system (not just the vid card, the entire system) draws. get a psu (seasonic recommended; antec is over-rated) that has 2x max wattage that your system will draw at load (so if max load is 300w, get a 600w psu). the reason is that psus are most efficient at about 50% load.
 
clone
Gerbil Elite
Posts: 900
Joined: Mon Mar 12, 2007 10:40 am

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Mon Jul 23, 2012 11:36 pm

.
Last edited by clone on Tue Jan 14, 2014 1:40 pm, edited 1 time in total.
neg
 
just brew it!
Administrator
Posts: 54500
Joined: Tue Aug 20, 2002 10:51 pm
Location: Somewhere, having a beer

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Tue Jul 24, 2012 6:55 am

clone wrote:
Phildoe wrote:
Should be alright, but I would never chance it. a 500w PSU can be had pretty cheap from the egg.

that is true but a quality 500 watt will cost triple that and in the end his Antec 400 watt is likely more than enough.

...and is probably *more* capable than a cheap 500 watt unit.
Nostalgia isn't what it used to be.
 
leftyassassin
Gerbil
Topic Author
Posts: 67
Joined: Wed Jun 16, 2004 2:57 pm
Location: Peoria, Arizona
Contact:

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Tue Jul 24, 2012 9:34 am

Wow, I never expected my post to garner this much discussion. Thanks again for all your input.

I decided to go ahead with a 7850, the MSI Twin FrozrIII. Seems like the sweet spot for the system I've built, plus I got it for $220, which is just about what I was willing to spend. I think I probably could have gotten a GTX 670 and been fine but I don't really NEED it. I figure rather than spend $400 on a GPU now I can spend half that and, in two years, get whatever new hotness is available at the same $200 price point.

Anyway, thanks again. Now if you'll excuse me, I have a UPS man to impatiently wait for.
 
vargis14
Gerbil Jedi
Posts: 1900
Joined: Fri Aug 20, 2010 6:03 pm
Location: philly suburbs

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Tue Jul 24, 2012 10:02 am

Hey lefty so what did you decide on? I hope the 7870, although the 7850 is also a fine choice and they both overclock great. Overclocked i think the 7850 runs just as fast as the gtx580 at less then half the voltage. The 7870 overclocked beats it at half the the voltage along with 2gb of memory over the 580s 1.5gb.

I wish i could trade my 1ghz stable EVGA 560ti Superclocked cards for a pair of 7870s...even 7850s. I cannot wait until the 7850s are 200$ and the 7870s are 250$. They are definitely overpriced even with the current price drop, they outperform the 6970 and nip at amd's own 7950 with ease but i know they cost a heck of a lot less to manufacture then the 6950 or 6970 let alone a 7950. With many more chips per wafer and less power circuitry needs then there 6000 series parents.

So far the 7850-70 series of cards are the most efficient but powerful design among AMD's 7000 series cards. But that's my opinion
2600k@4848mhz @1.4v CM Nepton40XL 16gb Ram 2x EVGA GTX770 4gb Classified cards in SLI@1280mhz Stock boost on a GAP67-UD4-B3, SBlaster Z powered by TX-850 PSU pushing a 34" LG 21/9 3440-1440 IPS panel. Pieced together 2.1 sound system
 
cynan
Graphmaster Gerbil
Posts: 1160
Joined: Thu Feb 05, 2004 2:30 pm

Re: Can my PC's 400w PSU handle a Radeon HD 7850?

Tue Jul 24, 2012 11:47 am

vargis14 wrote:
I hope the 7870, although the 7850 is also a fine choice and they both overclock great. Overclocked i think the 7850 runs just as fast as the gtx580 at less then half the voltage. The 7870 overclocked beats it at half the the voltage along with 2gb of memory over the 580s 1.5gb.


I don't imagine you'd have too much luck achieving high overclocks on an HD 7870 with a 400W PSU, especially if you start raising voltages by any real margin. But by all means, give it a try if so inclined. If you have one of those inexpensive kill A Watt, you can get a rough idea on system power draw when pushing your card at higher clocks.

Antec, like most other PSU "manufacturers" gets most if not all of its power supplies from OEMs. They have models that compete with the best of the best enthusiast power supplies, such as the HCP-1200 and new HCP-1000 Platinum, made by Delta, as well as some more mediocre PSUs they've sold over the years. I would agree with the sentiment that, in general, Antec PSUs are above average (including the OP's), but because they source them from different OEMs, you really need to take each one as they come.

Who is online

Users browsing this forum: No registered users and 1 guest
GZIP: On