i have been thinking of buying this hardware .. what you guys think its still profitable ? how long will it take to break even

It will generally take several months at the very least to ROI with the most efficient hardware right now (S5 included). People who purchased when it was first released should be able to ROI in a month or two depending on their electric costs and the luck of the pool(s) they were using.

It would probably be most profitable to buy a miner when BTC is high, mine for a few months and then sell it when BTC is low - you should be able to profit in terms of BTC

After upgrading all the S5's and scoping out the temp charts, I picked a miner with the highest fan speed and temperature and took it offline. (Note to Bitmain: add a cool-down cycle that is triggered by unplugging the net cable).  After an air blast in the garage to get rid of the dust, proceeded to take off the fan and end brackets using a folded piece of cardboard to separate the fins on the heat sink.  Next, I removed one of the two ASIC boards with the dozen or so spring screws (clever!) and noticed that the thermal compound on the 1384 chips was mostly missing !  Maybe an unfortunate over-heat in a prior life, who knows.  After cleaning up the heatsink and board with contact cleaner followed by iso alcohol, I applied some GELID Solutions GC-Extreme thermal compound to the chips, installed the first board, ditto for the second one.

Bottom line, new thermal compound resulted in 600 RPM fan reduction and 8-10 Deg C in temperature !  Took about an hour for the first one and $5.00 in Gelid compound.  Happy camper here !

i hate to say it but at this point in time, if you dont have other hardware to help roi new hardware i dont think its wise to purchase new hardware.

not unless they come out with much faster cheaper hardware that uses a lot less energy.

diff going to be 50b soon.

you will end up with exactly what you put into it 6 months down the road..
yes BTC might go up, and you will make more.. but..

gambling on the BTC going up is the same as just buying it and holding it.

No fun in that though I like hearing the whir of a miner!

Impressive results!  What is your ambient temperature?  Please share more details on exactly how you applied new compound.  Thank you.

Thinking of two S5, outside of footprint, is there a real compatibility advantage to buying one EVGA Supernova 1300 Gold Vs two Corsair CX750M Bronze?  I understand the CX750M measures as an 825W supply (per Dogie), so it seems to me the reason to choose the 1300 is less space and fewer power cords.  Right or wrong?

Overall you'll have less loss using a single, larger PSU versus two individual ones.  Granted, its not much loss, but hey, electricity is electricity.

that is a pretty large gap..
board #1 is hotter on mine then #2 but only by 6c.

id wait till the diff increase to take it down and repaste it.. its going to be a big increase and id mine as much as you can before.

@Digitalmocking

Temperature difference between the 2 hashing PCB was reported to the engineers and it was reviewed.  So far, it is not the hardware caused issues, but rather where and how the miners are being deployed and managed per the engineers.