New computer build, old PSU. Do I have enough power?

[amberion2dp]

I'm doing a major gut/replace job on my aging computer. My concern is whether the replacement parts will be getting enough juice from my PSU.

What I have currently:

PSU: NSpire NSP450P4DL 450w +3.3/28A +5/40A +12/25A
MOBO: ECS K7S5A, Integrated LAN
CPU: Athlon XP 2200+ Thoroughbred
Memory: 2x512 PC2100 DDR SDRAM
Video: Geforce FX 5500 AGP 128MB
Sound: Sound Blaster Audigy ZS PCI
HDD: Maxtor 5100RPM 20GB IDE
DVD-ROM: Sony Generic DVD-ROM Drive

I have planned on getting:
AMD Athlon X2 Brisbane 4000+ 2.1GHz 1000MHz FSB 1MB Cache AM2
ASUS M2V-MX SE AM2 Motherboard
ASUS Radeon EAX1950 Pro 256MB 256-bit PCI-E
Generic (Corsair) 1GB DDR2 RAM PC2-6400

Will my power supply unit be sufficient, do you think?

 

[akhilles]

Miminum requirement is 450-Watt & 30 Amps on 12 volt rails.

 

[englandr753]

That looks like a lower end PSU. It may be worth getting a better quality PSU. I would.

 

[amberion2dp]

It's actually quite a good P4 type PSU, but the technology is old. I've heard some reports that the 30A requirement on the 12v rail is overstated, that 22A will be sufficient. I figure with the power-efficient brisbane, ddr2 ram stick, I'll likely be using approximately 90ish Watts. Add in a PCI sound card for another 5 watts or so, I've heard the x1950pro also pulls about 66 watts(call it 70 to be safe), so I would be pulling 160watts from the 12V rail, which has a max wattage of 300. Are my numbers right or am I missing some component? Most of the other computer components are on other rails, I think?

 

[jsc]

All right. You now have three replies suggesting that you also replace the PSU (me, also), but you still want to use your old PSU.

The better PSU's provide full rated output at 50 deg.C. (122 F.). This is a difficult enough specification to meet, that if a manufacturer can meet it, he will tell you. You can pretty much assume that everyone else uses 25 deg. C. (77 F.). Some of the better manufacturers also provide output verses temperature graphs. These indicate that the output needs to be derated (reduced) by 1 - 2% per degree C. over rated temperature. This means that, as your PSU reaches operating temperature of 40 - 50 degrees C. (if you are lucky, it won't go higher), your 450 watt PSU will turn into a 350 - 400 watt PSU.

But, go ahead. If it works for you - great. If you run into stability problems (primary symptoms probably will be random reboots or lockups), you will know what to replace.

 

[amberion2dp]

Yeah, you're right about that jsc, and thanks for the reply, I appreciate it. I'm on a limited budget(I don't think I mentioned that before, but it's one reason why I don't want to replace the PSU-yet-I can't afford to), so I can't replace everything all at once. It may be that down the line I'll have to get an antec earthwatts or something similar, but for now I'll have to use what I've got.

 

[hairycat101]

The PSU is very important. It is the only piece in your box that can fry everything else. I would really, really, really recommend getting one with multiple rails.

 

[englandr753]

I think your PSU will run your new items but for how long is the question. Its always safer to have suitable hardware that is responsible for the functionality of every other (more expensive) components in your system!

Roll the dice if you must...

Go here for reassurance:
http://educations.newegg.com/tool/psucalc/index.html

 

[englandr753]

This calculator seems a little high to me. You may want to find a second calculator to check and compare specs. It told me I need 713 watts and I have a 700 watt PSU. This is estimated so it could vary give or take.