So i have an Optiplex 745 SFF and im planning to add in the HD 6570 1GB DDR 3 as soon as i receive it next week. The problem is that i don't think the current air flow will be sufficient for the GPU. I have a 5v fan that has a 2 pin plug in i guess and i see a 2 pin on the mobo but im not sure if thats what its for.
Now, if that does not work would i be able to plug in a regular fan into that 3 pin?
Or should i just buy an extra Dell 5 pin cpu fan and replace the small HDD 5 pin fan thats already there?
The small form factor Dells have an interesting CPU cooling setup that really should not be modified. Personally, I would just put the new GPU in and worry about additional cooling later. I wouldn't think your temps should be that bad. Most GPU's draw air in from the case and exhaust it out the back (there are exceptions). I think fitting it will be your biggest issue.
Nothing I see in those pictures is a fan header - the arrow points to a jumper on the mobo, not a power header of any nature. The three pin in the lower right of the second picture appears to be a propriety header (I can't tell what off hand) but won't fit a three pin fan.
If, for some reason you do need a new fan, best to purchase it from Dell.
I was thinking of purchasing a new 5 pin CPU fan and replacing the small 5 pin HDD fan and relocating the HDD. The only thing im worried about is that there is no exhaust. I believe that currently the CPU fan is pulling air in to the case, would it be better to turn it around?
That connector will work to power a standard 3 pin fan from the propriety header I couldn't identify earlier (bottom right hand corner of pic 2).
You don't want to change the intake fan direction since it does the intake portion while the power supply acts as an exhaust.
I did look at the video card and noticed that it does not exhaust out the back... that may be a heat concern in such a limited area but since the power supply is right next to it, heat shouldn't linger in the case.
I just can't figure out where another fan might fit...
The thing im worried about is that the PSU heats up alot when the cpu fan is on intake. Do PSU's have a high allowance for temperature? And for the extra fan im thinking of cutting the Hdd tray since i have a 2.5 and put an 80mm over the chipset.
As a rule PSU's get very finicky with heat (many do not rate themselves above about 70C ambient) - but, as long as you are not stressing your power supply (ie. going over 85% of it's stated wattage capability) and your intake into the PSU is under 70C (~158f) your PSU should handle it.
Your fan mounting idea sounds good.