please help me understand if I will need a new PSU

[sysdawg]

I am planning on a new GPU as a Christmas gift for my son, it will go into an old PC. Trying to figure out if I can get away without a new PSU. The salient points:

Dell Vostro 400 MT minitower, circa late 2007
Intel E6850 - 65W TDP
LGA775, Intel G33 chipset
new GPU - GTX 660 - 130W TDP
assuming additional 90W for motherboard/chipset, 4 DIMMs, HDD, DVD drives

285W total, vs
300W PSU, made by Delta

The PSU indicates max
12V 18A
3.3V 17A
5V 22A
3Vaux 2A
-12V 0.8A
5V plus 3.3V can't exceed 160W

Lastly, I believe that the the same PC, with the same 300W Delta PSU, was offered with an 8800 GT as an option - 105W. So my intended GTX 660 is only 25W more than that.

Will the existing PSU suffice?

Thanks in advance for any replies.

 

[lehtv]

For a GTX 660 you would need a new PSU. The 300W Delta unit doesn't have even a PCIe power connector. Official minimum requirement for GTX 660 is 450W.

In addition, the CPU in your son's build can't really handle a graphics card as fast as a 660. I would not combine an old Core 2 Duo with anything more than a 7750. That one doesn't actually require additional power cables so you should be OK with the current PSU.

 

[sysdawg]

Actually, the old card uses a single PCI-E 6-pin power connector, and so does the GTX 660 (regular, not Ti), so that part shouldn't be a problem. The real question is the 12V limit on the PSU...it is specified as 18A.

 

[TemjinGold]

I wouldn't do it, especially since the rest of that machine is too slow to make much use of a 660 anyway. 18A = 216w.

Are you using the 8800gt right now?

 

[sysdawg]

Are you using the 8800gt right now?

No, currently 8600GTS, I was saying the 8800GT 105W TDP was an option originally, with the same PSU as I have.

 

[lehtv]

The GTX 660 is still a bad choice to pair with a slow Core 2 Duo.

 

[Fallengod]

I dont quite see the logic in skimping on the PSU. You can find 600+ watters for $20-30 often times on sale. Youre going to risk the components in the system to save $20.... Seriously? : /

You should not run systems up to the very max limits of the power rating of a PSU.....

 

[Eureka]

There's a Corsair TX430 unit that goes on sale for $20-30 quite often. Pick one of those up and don't worry about power issues again. That being said, you probably would be able to run a 660 off there, but it'd be at its limits and you might even see power cutting out at peak moments (which if it's a good unit should not hurt the components, if power protection kicks in).

The main thing is definitely the CPU... you can put a 660 in there but you'll be bottlenecked. Perhaps a 7770 (around $100) will be a decent upgrade from the 8600 GTS.

 

[TemjinGold]

I dont quite see the logic in skimping on the PSU. You can find 600+ watters for $20-30 often times on sale. Youre going to risk the components in the system to save $20.... Seriously? : /

You should not run systems up to the very max limits of the power rating of a PSU.....

The "logic" may be that money is tight. The OP is trying to get something nice for his son and perhaps the cost of the card alone is all that can be afforded?