Do I need a new PSU?

[Freak'n Big Panda]

I just bought a new motherboard (DFI NF4-D) and graphics card (7800GTX) and I just realized while putting my system together that my old 420W enermax PSU (from '02) doesn't have either a 24 pin ATX connector or the 6 pin PCi-E connector the 7800GTX calls for. My local computer stores sells the 20 to 24 pin connectors but the sales man told me he has never even herd of a adapter to convert the 4 pin molex to the 6 pin PCI-E connector. So do these adapters exisit (I'd be VERY surprised if they didn't) and if they do where could I buy one (I'm located in canada if that matters)?

 

[BRiT]

I just bought a new motherboard (DFI NF4-D) and graphics card (7800GTX) and I just realized while putting my system together that my old 420W enermax PSU (from '02) doesn't have either a 24 pin ATX connector or the 6 pin PCi-E connector the 7800GTX calls for. My local computer stores sells the 20 to 24 pin connectors but the sales man told me he has never even herd of a adapter to convert the 4 pin molex to the 6 pin PCI-E connector. So do these adapters exisit (I'd be VERY surprised if they didn't) and if they do where could I buy one (I'm located in canada if that matters)?

Short answer: Yes. You need a new PSU.

The DFI NF4-D absolutely needs a genuine 24pin PSU. If you read over at their support site (DFIStreet), you will see a post by them saying warranty is void if not used with a 24pin PSU with ALL the additional power-plugs connected. Not only that, but if you use a 20pin PSU, even with the 20-to-24Pin adaptor, you WILL kill your memory.

DFI REQUIRES native 24-pin ATX molex & 480W for all the DFI N4 mobos.
http://www.dfi-street.com/forum/sho...22&postcount=34

 

[incurable]

... but the sales man told me he has never even herd of a adapter to convert the 4 pin molex to the 6 pin PCI-E connector. So do these adapters exisit (I'd be VERY surprised if they didn't) and if they do where could I buy one (I'm located in canada if that matters)?

There are adapters that convert two 4-pin Molexes (the inline ones you need on harddisk/optical drives, not the square ones that you plug into the motherboard) into a single, 6-pin PCIe power plug. Link w/ photo:

http://www.frozencpu.com/cab-70.html?id=23Hy2exG

 

[hughJ]

Your old model 420watt probably won't have enough amps on the 12v to run your system stably anyways.

 

[incurable]

Your old model 420watt probably won't have enough amps on the 12v to run your system stably anyways.

Given that it's a brand-name unit, I very much doubt that. I mean, I could run a 3.6 GHz Northwood, 1 GB Ram, an o/ced 6800 Ultra, 4 HDDs, a RAID-Controller and lots of other junk on a quality 350W unit with just 18A on the 12V line. PSUs are probably the most oversized component in today's enthusiast systems.

 

[Guden Oden]

Your old model 420watt probably won't have enough amps on the 12v to run your system stably anyways.

PCs really don't grab as much power as most enthusiasts believe, people tend to vastly over-estimate the size of the PSU they need. I call this the "americana syndrome".

A too big a PSU will just produce more waste heat when idling than one more closely specced to the setup's actual power need (efficiency rises with power draw, so more waste when doing nothing).

 

[Freak'n Big Panda]

K That's what I thought. I'll pick up an 24-20 pin adapter and one of the PCIe adapters tommorow then. I hate sales people btw. ALWAYS trying to mislead the customer, gets very annoying at times. Well w/e I'll return the PSU tommorow. Oh btw will 20amps on the 12V enough for my system? Cause that's all my PSU puts out.

 

[BRiT]

K That's what I thought. I'll pick up an 24-20 pin adapter and one of the PCIe adapters tommorow then. I hate sales people btw. ALWAYS trying to mislead the customer, gets very annoying at times. Well w/e I'll return the PSU tommorow. Oh btw will 20amps on the 12V enough for my system? Cause that's all my PSU puts out.

UHM, HELLO! Did you not read the official word of DFI that I posted?

Here, I'll repost it for you.

Short answer: Yes. You need a new PSU.

The DFI NF4-D absolutely needs a genuine 24pin PSU. If you read over at their support site (DFIStreet), you will see a post by them saying warranty is void if not used with a 24pin PSU with ALL the additional power-plugs connected. Not only that, but if you use a 20pin PSU, even with the 20-to-24Pin adaptor, you WILL kill your memory.

DFI REQUIRES native 24-pin ATX molex & 480W for all the DFI N4 mobos.
http://www.dfi-street.com/forum/sho...22&postcount=34

 

[Pete]

IMO, it's unwise to risk at least $600 worth of equipment (GPU, MB, RAM) just to save the $50-80 it would cost you to get a new, high-efficiency PSU that's geared toward the much higher +12V rail draws of modern CPUs and GPUs.

I suggesting browsing SPCR's PSU reviews to find an efficient and sufficiently powerful and quiet PSU for your needs. You can also check out SLCentral and XbitLabs for more PSU reviews and general info about the requirements of the latest ATX spec. SPCR's forums seem to be a good start to find the best prices on PSUs, but you can always use PriceGrabber or the like.

Enermax may be a good brand, but 20A is fairly minimal (chart here shows ATX 2.0 +12V spec to be 22A minimum, and that's just for what they consider to be a 300W PSU--400W requires 29A) for a top-of-the-line GPU, especially if you're pairing it with a high-end CPU and lots of HDs.

Don't skimp on the PSU. Spend some extra now, and you'll get a more efficient and quieter unit that will lead to less waste heat output (thus possibly lower case temps) and that will likely serve you well for years to come.

And you can probably sell your Enermax to recoup some of the cost.

 

[Freak'n Big Panda]

Brit, sorry if I offended you but everyond else that posted in this thread seemed to think that my 420 enermax would be fine for my system. Anyways I'm sorta getting some mixed answers here... not really sure what I should do. The PSU was $100 (Canadian) after tax and I could really use that money seeing as I'm a student with very minimal income. All of my parts in my system are close to bran new so they're still all under the manufactures warranty so it wouldn't be too big of a deal if I killed something. Anyways brit, why exactly would I kill my memory? Does RAM even feed off the 12v line? I don't think it does and my old 420watt is supiror in every repect to my new 485Watt enermax noise taker except in the 12v line.

 

[digitalwanderer]

I don't think it does and my old 420watt is supiror in every repect to my new 485Watt enermax noise taker except in the 12v line.

I don't know, I went from a TT420w to a 500w for me new mobo just because my 12v line sucked on the amps.

 

[Freak'n Big Panda]

did you try your old 420 watt before you bought the new 500w one? I think I'm probly going to stick with the new enermax I bought regardless (just cause it's so dam quiet) but I'd still like to know if 420watts w/ 20amps on the +12 rail is suffient for modern systems. Has anybody ever tried running a high end system with old PSUs like this one?

 

[BRiT]

Brit, sorry if I offended you but everyond else that posted in this thread seemed to think that my 420 enermax would be fine for my system. Anyways I'm sorta getting some mixed answers here... not really sure what I should do. The PSU was $100 (Canadian) after tax and I could really use that money seeing as I'm a student with very minimal income. All of my parts in my system are close to bran new so they're still all under the manufactures warranty so it wouldn't be too big of a deal if I killed something. Anyways brit, why exactly would I kill my memory? Does RAM even feed off the 12v line? I don't think it does and my old 420watt is supiror in every repect to my new 485Watt enermax noise taker except in the 12v line.

The thread in DFI-Street is quite long, but have a full read. Not sure if this is from a component on the motherboard faulting if not supplied with proper power which then cascades to other components which then leads to the memory. It was hard to get an actual causation explaination or if it only happens when using higher than 2.8volts on the memory. They also didn't say if there was possibility of other components faulting if not supplied with enough power that might effect CPU or Video card.

The one thing they absolutely made clear was the absolute need for a genuine 24-pin PSU and additional power-connectors being plugged in and that they would not cover any RMAs caused by not following the stated requirements.

I understand you're under a budget, but why risk $600-$900 of parts to save $50 or so?

 

[Pete]

I'd still like to know if 420watts w/ 20amps on the +12 rail is suffient for modern systems.

Not according to the ATX 2.0 300W spec that's listed in my second link. That said, the first link shows an A64 + 6800GT system drawing just 8A when the CPU is stressed, and probably a couple amps more when the GPU gets involved. (For instance, according to Kill-A-Watt, my PC draws 133W idle, up to 158W with Prime 95 stressing the CPU, and up to 178W in 3DM01SE: Nature.)

Minimal income or not, you should consider a new, ATX 2.0-spec PSU as a required purchase for your not-so-minimal 7800GT.

Yes, people have run studly cards on lesser PSUs. SPCR has a whole thread dedicated to "look how much I can run on my old 300W PSU," and I'm almost positive people have gotten 6800GTs to run in their ~250W Shuttles. But it doesn't seem like a risk worth taking, considering the DFI warning that BRiT posted.

My first link also shows you how many amps RAM uses on the various rails. It's fairly minimal all around, according to SPCR's equipment.

 

[Freak'n Big Panda]

alright yeah I think I'm just going to sell my old one. Like you guys have said it's just not worth the risk plus I'm fairly confident I can sell my old PSU for about $45 (CND) so the new PSU will only cost me $50 net. Not too bad.