btw, i was thinking that with all those FPGAs out there, is it cost effective to mine with VGA cards ? hmmm
FPGA still have a high capital cost.
Take Icarus board. 360 MH for $570. That is ~$1.6 per MH/s.
A 4x5970 rig can get 3000 MH so having equivalent hashing power using an FPGA would cost $4800 plus say $200 for power, host PC, usb hubs, and cables.
The non-GPU portion of rig (RAM, CPU, MB, PSU, USB stick, Linux) can be had for ~$400. @ $400 ea a 4x5970 system would cost ~$2000, @$350 ea a 4x5970 system would cost $1800,
FPGA (3GH/s) - $5000
4x5970 (@$400 ea) - $2000
4x5970 (@$350 ea) - $1800
4x5970 (@$300 ea) - $1600
Granted FPGA will use about 1/10th the power but depending on one's electrical cost it will take a long time to make up that difference. That being said FPGA will only get more powerful, more efficient, and cheaper. They will eventually replace GPU rigs but not today.