Virtually the only difference you'll see is if you overclock, imo I'd just go with a Haswell Xeon or save for a 6700k for Hyperthreading which is starting to increase performance in games.

How much would it cost for the 6700K Build ??????????

It depends, what is your total budget for everything?

if i waited i could have like 1200 EURO

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4c8t Xeon will be better for gaming as more games take advantage of Hyperthreading, Motherboard and PSU will support SLI for more GPU powah.

PCPartPicker list because Irish currency is a bish, but 832 GBP is roughly 1200 EUR. If the cost is over, then you could drop the SSD or HDD and add one in ASAP, but if you don't do much other than play games then you should be able to last on a 250GB SSD long enough to buy a HDD for mass storage.

I Already have a 1TB HDD and i have this case

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would they be worth using in the build ??

I don't see why this build wouldn't be fine.
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