Blanned :
Xtergo :
In the case of power supplies you don't want to cheap out they can fry your motherboard graphics card or any other component in the system. For a gtx 770 I would go for a 650W PSU atleast or more because that Xeon you have in there takes some decent amount of power.
If you arent willing to spend much there isnt any option left.
Btw why are you buying a Gtx 770 ? there are cards now available for the same price that perform miles better ie 970 used for 190$ and RX 480 for 200$ ect.
All good Sfx power supplies are 100$-150$ so it might be better if you consider a casing that can support a full size ATX power supply that will be economical
Because it would bottleneck my 9 years old xeon harder.
Sorry but this is how I explain things bare with me xD
People are afraid like "OMG its a BOTTLENCK!!! The processor will EXPLODE!!! OHNO! what are we gonna do now ???"
Apart from my attempt at a lame joke, contradictory to popular belief if there is a bottleneck it is nothing to worry at all, If i paired my Intel Core 2 duo with a Gtx 1080 (Highly exaggerated scenario) there is gonna be nothing wrong but I would not get the same performance that someone with a better CPU like an i5 4690K would be getting.
Bottlenecks do not put any strain on the processor they will give the same effect as someone with s slower graphics card.
so I would suggest putting a used 970 or something like that and it wont give u any significant bottlencks considering tha thte AMD 8 Core's have about the same IPC (per clock performance) of the the Intel core 2 duo, core 2 quad and Your Xeon 's era.
Get the best graphics card you can afford, I hope people begin to realize that.
If you go deeper into this topic I would say there is no such thing as a bottleneck but a better term would be to say, "unoptimized" system.