PSU query for hd3870/3850

[TheBigfootNZ]

Hi ya, long story short.

Currently putting a system together to replace my old one since my old crt went kaput and my antique of a graphics card cant display anything in my nice new 22' at its native resolution of 1680x1050.

Anyway due to being strapped for cash ive had to coble the new system from oldish parts (or getting old by todays standards) and ive pretty much worked it all out however after doing some reading Ive learned how important ampage is on the 12v rail for graphics cards and I cant realy find any concret evidence my old PSU will suffice, although for the Wattage power calculators all say its fine wattage wise but cant get any info on the amps. So my question is...

Given the following components is my older PSU sufficient to power the graphics cards (and all else) or will i have to invest in a new PSU as well.

The system will contain-

Cpu:- Intel core 2 duo E4500
MB:- Asus P5K intel p35
PSU:- Thermaltake Purepower 420w (18amp on the +12v rail) From my old system.
GPU:- Sapphire Radeon HD3870 (or a HD3850, havent decided yet)
+ the usual, CD, usb mouse, graphics tablet etc...

Im hopeing my PSU is sufficient but if it isnt Ill just have to fork out more cash for a newer one.

Thanks for any help

Eit:- i did find a list of graphics cards and their amp usage and it mentions the HD3870 and 3850 both taking 18amps, however im unsure just what that means.

Bigfoot

 

[Engineer]

I'm running an E6300, 2GB of OCZ ram and an HD3850 - 512MB version on an Earthwatts 380W and it doesn't even make the fan run very fast or loud on the supply. I would think that you're fine with that supply and combination of components.

 

[TheBigfootNZ]

Originally posted by: Engineer
I'm running an E6300, 2GB of OCZ ram and an HD3850 - 512MB version on an Earthwatts 380W and it doesn't even make the fan run very fast or loud on the supply. I would think that you're fine with that supply and combination of components.

Hmm nice, thanks for that. What sort of ampage does your PSU have on the 12v rail?

 

[*kjm]

It's not on the certified power supplies list... you can look for one that will work here . I would look into one with the newer 8pin PCI connectors for upgrades down the road.

 

[MoMeanMugs]

Certified = paid money to AMD/ATI.

 

[TheBigfootNZ]

Engineer ive noticed your powersupply has 2x +12v rails. Mine however only has a single 12v rail... would this in anyway effect my setup, since yours technically has alot more ampage?

 

[thilanliyan]

If I were you I'd invest in a new PSU. You can get a fairly good one for like $60-70...I'd say get a Corsair or OCZ one. I've had 2 Thermaltake PSUs die on me so I myself won't use any of their lower end ones. I've heard their high end ones use good components though.

 

[TheBigfootNZ]

Heh aye, although im from New Zealand and prices here are ... well, bareable to "you want how much?!".. Then again im thinking its probably something ill have to just bite the bullet and do (i originaly expected this to only cost me around 600$ or so, far its just gone over 1000$, if i also decided to get a new case).

 

[*kjm]

Originally posted by: MoMeanMugs
Certified = paid money to AMD/ATI.

And your point? If they send a supply to be certified to any company they would be charged right?

TBFNZ I would upgrade if it were my setup because if a supply fails a lot of the times the supply is not the only thing to go. Also in the next upgrade you do you will need it. Think of it as the heart of your system.

 

[Engineer]

Originally posted by: TheBigfootNZ
Engineer ive noticed your powersupply has 2x +12v rails. Mine however only has a single 12v rail... would this in anyway effect my setup, since yours technically has alot more ampage?

Yes, I just noticed that your power supply is indeed older and places quite a bit of the current toward the 5V and 3.3V lines instead of the 12V rails. To be honest, I'm not sure now that your's will work or not. I assumed that the Purepower was a newer variety of PS and had better loaded 12V rail(s). Sorry for the wrong assumption.

 

[*kjm]

Originally posted by: Engineer

Originally posted by: TheBigfootNZ
Engineer ive noticed your powersupply has 2x +12v rails. Mine however only has a single 12v rail... would this in anyway effect my setup, since yours technically has alot more ampage?

Yes, I just noticed that your power supply is indeed older and places quite a bit of the current toward the 5V and 3.3V lines instead of the 12V rails. To be honest, I'm not sure now that your's will work or not. I assumed that the Purepower was a newer variety of PS and had better loaded 12V rail(s). Sorry for the wrong assumption.

Engineer for only being on the forums for two days more than me you have a heck of a post count


I agree one rail 18A..... I would not do it.

 

[Engineer]

Originally posted by: *kjm

Engineer for only being on the forums for two days more than me you have a heck of a post count

LOL. You haven't looked at some of the other 65,000+ posters have you?

Most of mine was during my days of Distributed Computing when I was recruiting heavily for the TeAm!!!

 

[thilanliyan]

Originally posted by: TheBigfootNZ
Heh aye, although im from New Zealand and prices here are ... well, bareable to "you want how much?!".. Then again im thinking its probably something ill have to just bite the bullet and do (i originaly expected this to only cost me around 600$ or so, far its just gone over 1000$, if i also decided to get a new case).

Lol yeah I lived in Australia for a little while so I know computer prices in that region are not cheap. Try to find one on eBay if you can...that might help with the cost. ALso, you might be able to get away with substituting the E4500 CPU for something like a E2180 (or even a E1200 which should overclock fairly well) which should be much cheaper. I built a system for a friend recently with a E2180 and overclocked it to 3.2GHz (it was easy since it had a 10x multiplier so no need for super high fsb)...at that speed it wouldn't be too much of a bottleneck, even with the reduced cache.

 

[imported_Scoop]

A Quality 300W PSU is enough for those cards and your system but I'm not sure whether your old Thermaltake is such a unit. As you can see in my sig, I'm running a pretty similar setup with a 330W Seasonic.