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Homebrew Modular PSU

R

redivulpis

Limp Gawd
Joined
Sep 10, 2011
Messages
223
Hey guys, In the next few weeks I'm going to be getting my hands on THIS PSU for my SFF build. I'm looking to minimize the number and length of cables on this bugger, but I'm not in a great hurry to burn my house down in the process so rather than snip the extra cables (8-pin Intel Power cable is relatively useless in an AMD system) I'm going to instead make the PSU modular. I figure the best way to isolate unused cables is to actually use them, but not use them. I'm sure that makes sense to someone. Anyway, I do plan on single sleeving and shortening the ATX24 and 4-pin power cables, as well as the SATA power cables, most likely by snip-and-resolder, unless I can find an inexpensive way to recrimp them.

So, in order to do the modular conversion, I've determined to use phono-plugs similar to the ones found on Hiper modular PSUs (actually a few are from my old 580w Hiper). For the 8-pin Intel Power cable I plan on using an 8-pin version of this plug.

Is there any reason this should not work? I'm really just kinda throwing the idea out there, as I plan to do it whether it's a good idea or not, but before I go chopping up an $80, I'll probably practice on one of my spares I have laying around.

I'll be sure to post pics of the prototype and the finished product if it gets that far!
 
If you don't have the PSU already, why not just buy a modular one?
 
Falkentyne: My Link-Fu seems to be lacking. The PSU in question is an FSP Group 450w MicroATX with 2 12v rails, and native SATA power (i.e. dedicated 3.3v line).

Matteos: I've looked all over and have not yet found a suitable modular MicroATX. I could go ATX, but considering the nature of the project (MiniITX board, custom case, etc.) I'd rather stick with the smaller form factor. Also, I'd planned on doing a full single-sleeve anyway, so I'm not concerned with voiding the warrany =P

Pischian18: YES. Those are exactly the parts I'll be using for my extensions. I have found an 8-pin for the ECS line that won't be used, so that seems like the best option. I did scavenge a bunch of the sockets from my Hiper PSU when it crapped out on me, so 4-pin sockets are not a problem. I can't decide on whether I should use an actual 2-pin for the 7th and 8th pins on the secondary PCIx power line (since they won't be used in this particular build), or to just use the 3-pin socket I ripped from the Hiper. In the interest of saving money on the project I'll likely end up just reusing the 3-pin, since it only had 2 lines (ground and 12v) when it was in the Hiper originally.

While I'm here I might as well ask about what I might expect in power draw, and whether a 450w will be enough.
Specs:
Motherbooard: ASUS M4A88T-I Deluxe---- no idea what the mobo draws
Processor: Phenom II x3 2.8GHz Heka - OC'd to 3.4GHz------------------------------------Avg. ~110w
Memory: Corsair DDR3 SO-DIMM 8GB (2x4GB)
Video Card: HIS IceQ X H687QN1G2M Radeon HD 6870---- Newegg recommends about 150w dedicated
SSD: Kingston 30GB ssdNow (temporary, will be upgrading to at least a 60GB)---Avg. -5w
HDD: WD Scorpio Blue 150GB Laptop drive (will be replaced with a VelociRaptor at some point) --probably another 5w
Cooling: Antec Kuhler 620

The above adds up to roughly 300, allowing for various cooling stuffs and whatevers. I don't have anything like a Kill-a-Watt to get an accurate measurement yet, but will probably cave and buy one sometime soon.
Considering the video card and CPU will be the greatest draws on power, with miscellaneous USB devices plugged in (KB, Mouse, USB 3.0 backup drive, etc.) I wouldn't think the max draw would be much greater than 350-400w, and with the PSU I have in mind I should have that extra 50w breathing room.

So, any fault in my logic? will my computer cry? do androids dream of electric sheep? if so do they ever make it to 11?


EDIT: OOOOH Big important informations. I do plan on bumping up voltage on the memory so as not to bottleneck the processor, but not for quite a while.
 
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I'm a NOT guru but from what I understand it's gonna come down to efficiency in your situation. The 150w is idle as far as I know. When you load anything intensive up that 6870 could push above 200w. (Gotta go check [H]) If the load efficiency isn't in the high percentage under load a 450w could really only handle 300w of draw before you crash. You need to find a review on the PSU actually getting beaten up.

http://hardocp.com/article/2011/05/23/gigabyte_hd_6870_super_overclock_video_card_review/8

Take a look at the power chart.

a standard 6870 draw 129w on idle. under load it can draw 287w.
 
450W is perfectly fine for that computer.
piscian18 said:
If the load efficiency isn't in the high percentage under load a 450w could really only handle 300w of draw before you crash.
Click to expand...
That is absolutely not correct. Efficiency affects the amount of power the PSU draws from the wall. A quality PSU can supply its full rated output, which is 450W in this case.
piscian18 said:
a standard 6870 draw 129w on idle. under load it can draw 287w.
Click to expand...
That is also not true. The numbers you're quoting are the power draw from the wall for an entire system. The amount of power that a 6870 draws from the power supply is considerably lower.
 
Zero82z said:
450W is perfectly fine for that computer.

That is absolutely not correct. Efficiency affects the amount of power the PSU draws from the wall. A quality PSU can supply its full rated output, which is 450W in this case.

That is also not true. The numbers you're quoting are the power draw from the wall for an entire system. The amount of power that a 6870 draws from the power supply is considerably lower.
Click to expand...

Aw my bad I misread that.
 
Thanks for the input guys! Look forward to some pics of my test psu sometime in the next few weeks!
 
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