Thanks very much for your replies, I've understand now.
As I'm a FPGA specialist, I would had programmed something, but even here, the Asics are more powerful

And the algorithms seems not to be optimizable...
Yeah,FPGA days are LONG gone,at least for bitcoin,I had a few from BFL before their 65nm fiasco back in 2012 or 2013.........

I think there is a altcoin or two that you can mine with em,have to use Googlefu to find em

You could try getting a few video cards & mine altcoins,the cards do hold their value fairly well & you can browse this section in the forum to see what's worth mining:
https://bitcointalk.org/index.php?board=160.0You won't make a whole lot in most cases but the power consumption & resale value is better than BTC mining ATM.
And you have a pretty big learning curve with all the diff algorithms using diff mining software to figure out & play with,lots to study & think on

Video cards break pretty easily with mining, though, and with a broken gpu, oftentimes the only thing you can even scrap out of those is the heatsink. FPGAs do have some coins that they can mine, but not really a lot. Generally, any coin that has some algorithm to stop ASICs will work with FPGAs. If you really do just need a beginner ASIC or GPU for mining and you don't care about its hashrate, check out the AMD series of cards. R7s do the job, R9s do it better. For a cheap ASIC, check on eBay or in the marketplace for Block Erupter USBs. They truly used to erupt blocks, but now their low hashrate and 2w power usage is perfect for learning about bitcoin. I still have a few, and they work just fine. U1-3s also work, are portable, and have a reliable hashrate with more modern ASIC chips. The u3 has the highest hashrate out of them all, with the u1 being the "worst" although a U2 is basically a U1 with a better heatsink. Gekkoscience Compacs are the most efficient miner for beginners, and boast a semi-current BM1385 asic. They're very tunable and use low amounts of electricity and people have gotten them up to 20+GH/S from the base 11 or so. There are many options, but truly if you want a good start with mining, just check out the antminer S9 or S7-LN. They feature the newest ASIC chips, although the S7 wont make you anything and the S9 is still debated about profit.