actually i think 300watts has to be good for ur config and 9800.. but i would had suggested you to go for 350 watts or above .. anyway.. if your machine with 9800 performs poorly ... u already know whats the problem... :)

My Config:
Epox 8KHA+
Athlon XP 1700+
2HDD 1DVD-ROM

PSU: SPI 300W (300W AMD APPROVED ATX PSU )
Model: FSB300-60GT

Assuming that's ALL you have in your system (meaning NOTHING else ... like a sound card or a modem or an ethernet card or a floppy drive or a CD-Rom drive) and that you're NOT over-clocking your system, then yeah. It's probably enough.

I'm going to use this forum to mouth off about my total disgust over Enermax products. This probably isn't the time or place to do it but I just had yet another Eneramx EG-651P go down the tubes on me. It's the 5 volt rail and this is the SECOND one to go south on me. Prior to that I had an Enermax 465P fail. Same thing. The 5 volt rail.

My latest EG-651P reads 4.4 volts on the 5 volt rail under load (running a game or anything CPU/GPU intensive like a benchmark). This is all in LESS than the past 2 years (about 1.5 years, actually). I have 2 friends who have had the SAME experience so AVOID ENERMAX products like the friggin' plague!!

I just ordered the Vantec 520 and it should be here on Monday. It's got a 52 amp 5 volt rail and SHOULD hold up just fine. That's about the highest amperage rating of ANY PC power supply I know of. I have another buddy who lives out in the desert who just put one in his system. It gets REAL hot out there and he's very happy with the Vantec (so far).

I have a LOT of hardware in my system though. Here's the run-down -

Epox 8RDA+ motherboard w/ XP 2100 running at 2.5GHz with a Swiftech 226 watt TEC water block. It's running off it's own dedicated Mean-Well 350 watt 12 volt power supply though so that's not an issue. I can push it to 2.6 GHz easily but it's just not stable enough for anything other than benchmarks.

Hard drives - 3 Western Digital 120GB 8MB buffer EIDE drives. Two of them are running in RAID 0 mode off a HighPoint HPT374 RAID card. The other one runs off the controller on the motherboard. I also have a Seagate Cheetah 15000 RPM 18GB Ultra SCSI drive that I use for my Windoze boot partition. It's running off an Adaptec 29160 Ultra160 SCSI controller. VERY fast drive.

CD/DVD - a Plextor 12x10x32 S (SCSI) CD burner which also runs off the Adaptec 29160. Also have an ASUS 48x16x48 burner for when I'm in a hurry. The Plextor drive is probably THE best CD ripping drive ever made so it's earned it's place in my system. Then there's the Panasonic DVD burner (LF-D321). It's slow but it works and I can also use DVD-Ram (rewritable) cartridges.

I'm using the chip on the motherboard for my network adapter (Ethernet). It works fine too. For sound I have an Audigy Platinum that I'm about to upgrade to the Audigy 2. The front panel extender will work with it as well so all I need is the OEM version of the card. So, there's the front panel thing mounted in the case as well along with a Digital Doc 5 to monitor temperature sensors and power supply voltages.

Then there's the video card --- brand new ATi Radeon 9800 Pro with a Swiftech 80 watt TEC water block. The Peltier devices run off the +12 volt rail so I kNOW that's not what's dragging down the 5 volt rail. Besides, 80 watts (assuming it really does draw that much power) for the TEC just isn't enough to stress a 550 watt (650 watt peak) power supply. There is also an Eheim 1250 water pump (>300 GPH flow rate) and another water block on the NForce2 chip (the northbridge equivalent).

Fans and radiators --- twin radiators (one for the CPU and one for the GPU) both sandwiched between pairs of 120mm adjustable speed fans (that's 4 fans so far). I have all this junk stuffed into a Lian-Li PC-76 aluminum case which is VERY big. There are 4 more fan (80mm each) mounted in the lower front of the case that provide cool air in (intake). Now we're up to 8 fans. There are 2 more in the upper rear of the case that are (as I recall) 92mm each. That's 10 fans so far. ALL of these fans run at very low RPM so they're very quiet. There's also a floppy drive and one of those 5.25" drive bay fan things that holds another 92mm fan to suck hot air out of the top of the case and push it out the front.

NOW you know why I need a 500+ watt power supply. Under load, the +12 volt rail stays rock solid at 12.14 volts. It's the 5 volt rail that sags to under 4.5 volts that's the problem and has been the case with my last 2 Enermax power supplies. The two friends I have that had the same problem with their Enermax supplies don't EVEN have the amount of hardware in their systems so I KNOW it's not the load I'm putting on it.

There are LOTS of power supplies out there made by LOTS of different companies. A good rule of thumb is to buy 100-120 watts MORE than you think you need ... because eventually you WILL add something to your system that WILL drag down one (or more) of the voltage rails. Just don't piss your money away on Enermax products. They're WAY over-priced and if they last a year, you're lucky.

Later.

Detail Configs:
Athlon 1700+
512MB DDR266
PCI: Modem, TV Capture Card, SB Audigy
AGP: Radeon 8500
2HDD, 1DVD, 1Floppy

Current CPU Load: 100%



Is it ok to change to R9800 PRO with an increased ~24W? (R8500 needs ~30W & R9800PRO needs ~54W)

Thanks again! :wink:

12V is a bit weak but OK .... if you don't go any lower ... this could damage your hardware ... so if you upgrade to more power hungry parts a PSU upgrade would be sensefull ....
I got a "gold" 420W PSU for 30€ in ebay

I really like the Antec TrueControl 550-watters. I've got two of then that I subject to lots of weird torture without a single glitch because of them...

Please think about :
300W 350W or 420W and 550W means nothing - there are very good 300W PSU being better quality than "El cheapo" 550W PSU .
Example Q-Tec : All PSU are poor quality ecept for their 550W - looks somewhat OK but a quality 400W PSU should be better

Most important values are the Amperage ratings on 3.3V 5V and 12V and the most important value of all is TCO(Total Combined Output) on 3.3V+5V in Watt .

Example of a good quality 300/350W PSU : 20A on 3.3V 30-35A on 5V and 160-180W TCO

@ccso : Get a better quality PSU and not an "El cheapo" with big wattage but low amperages and overall poor performance