This unit can overclock, but needs some cool air.

-5C intake air, 412.5MHz, 53-56C temps, 1.32TH (1.35Th expected). Any higher than 412.5MHz seems to result in losing hashrate, even if temperatures are kept under 56C
-5C intake air, 400MHz, 51-54C temps, 1.32TH (1.35Th expected).
17C intake air, 400MHz, 61-65C temps, 1.32TH (1.33Th expected). almost no HW errors at this temperature.

This is with the stock fan connected to a 7V power, no PWM. Its about 3000RPM approx.

My next step will be to swap in an S1 fan at 7V (about 2/3 the airflow) and see what happens. Should be very manageable volume, but to keep temeratures under 65C it will need either a cold intake at 400MHz or warm intake at stock 350MHz

not sure how to easily do this without a PSU capable of 13V at >60A, or even colder intake or higher airflow. temps are 55/53C with the back end of the heatsink reading about 33C where it contacts the PCB. using a cheap infrared thermometer, readings on the PCB range from 45-65C

i dont get much HW errors, but hashrate seems to peak at 412MHz, at 425MHz its back down around the same speeds as at 400MHz

the built-in PWM settings are pretty high. I think if you use a cooler air intake you could run 90cfm fans and as long as the temps are <60C you should be just fine. Im running the stock fan on 7V w/o PWM (approx 3000RPM) and overclocking with -5C intake air and 54-56C temps

yeah, assuming theres no random limitations, you could upgrade a C1 with S5 boards as long as the heatsinks/liquid can keep pace

if you have cooler air for the intake and can handle the noise, then yeah theres definitely some room to overclock. 400MHz seems to be no sweat with a pair of 650W PSUs (I was achieving 387.5MHz on a single 650W gold (612W limit on 12v) without tripping the supply, but cables were warm so i brought in a 2nd PSU to go further

The S5 has some serious overclocking potential! 1.3TH seems to not be a problem and 1.4TH may be possible. (and its likely that efficiency will not change significantly)

as part of my thanks for a demo unit i advised bitmain several things to make this a "home miner" (as it is the S5 is excellent for large deployment i think). I suggested a S5-silent model that costs $20 more and includes:
1) top and bottom shrouds made with the same light durable plastic as the sides. nothing fancy or bolted down zealously.
2) a second fan, OR adjusting the temperature monitoring and PWM control to keep the fan speeds down (running at 3000RPM for 40C is silly, 2000RPM and 50C would be more like an S3)
3) default speed of 325MHz. a few percent cooler/slower/quieter and easily ovewrclocked at the expense of noise

nice fan, but i think the noise problem is an issue with the PWM settings. allowing th eboards to have a higher temperature setpoint would help a lot.

53C & 3850RPM at stock is a lot of noise, but i think up to 58C would be acceptable
39C & 3000RPM at 225MHz is silly though. the fan should drop to 2500RPM or less and let the temps idle closer to 50C.

Im running off -3C intake and the fan is approx 3000RPM at 7V with 375MHz speeds and <54C   (using PWM drives the fan to 3950rpm and the temps only go down 3-5C)

Im finding the temperature readings of the device are less than they *could* be. Using -3C inlet air, the air blowing at 3000RPM through the heatsink comes out at less than 25C. Connecting to the board's PWM jumps to insane speeds like 3850RPM though.

ps: built a shroud of packing tape and put the fan on a 7V source to keep it slow around 3000RPM. Board temps are 53/45 running at 375MHz (about 1.24TH)

would be easy. the PCB screwholes are laid out identical to the S1 and S3 as far as i can tell. you could strap S5 boards to a C1 probably

It looks to be the exact same heatsink with holes in all the same spots, but I dont want to dissassemble everything and much up the thermal paste to confirm if its millimeter-for-millimeter identical. Im pretty sure it is though.

I added an S1 fan as a secondary, and it helped a bit, but barely. Now i have two loud fans. Also added a bit of clear tape to the top as shrouding and i think that helps, perhaps even moreso than the pull fan did. I think Bitmain needs to include a top shroud made of the same flexible thin plastic as the sides - a lot of airflow is lost out the top, just like it was in the S1

no problems here. after 50min its averaging 1.16TH and looks to be similar results at the pool (eligius needs 3hrs to give a good stat though)
https://bitcointalk.org/index.php?topic=908494

conclusions: good miner, easy to use, but could use some improvements to reduce the power draw and fan noise to make it good for the home user. (ITS LOUD)

To preface this review, I have owned, operated, and over/underclocked S1, S2, S3, and S3+ hardware from Bitmain, as well as Bitfury, BTCGarden, SP10/SP31, and rockminer hardware. Bitmain asked me if I would like a demo unit of the S5 and I was happy to say yes, as it was an interesting piece of hardware with pre-conceived opinions.

I want to make this review focus on some of the details that others might not. I want to use the miner with a smaller PSU and focus on specific issues rather than waste time and text talking about things like efficiency and overclocking, as this information is already available from several other reviews and threads.

UNBOXING: This is a breeze. pretty much the exact same as an S3 unit; bubblewrap, 1 peice of tape, foam clamshell, beat-up cardboard box with staples keeping it securely sealed
SETUP: Again, a breeze. Plug in power, plug in ethernet, turn on. It uses DHCP this time and findes itself an address (in my case .135). Use an ip scanner to locate whaich ip it chose. in comparison the SP-tech hardware is very easy to find via http://start.spondoolies-tech.com/.
POWER: I am using a Corsair CS650M GOLD PSU. It has 2 paired PCIe cables (4 connectors total). I used one paired cable per blade of the miner.
MINING: Once connected the unit began mining. accessing the web interface with root/root as before presents the well-known interface and after entering my eligius credentials I have 1.17TH speed average over 20 minutes. This miner is easily capable of meeting spec right from the box, compared to the SP20 which only achieves spec in very cold environments.
NOISE: This is not an S3 - its much louder. The fans run at 100% for the first 10 seconds at boot, then tame down until the unit starts hashing and heats up. at that point, fans are up at 3600-3900 RPM (according to GUI) and loud. Sound is almost identical to a vaccuum cleaner, and sounds similar to a 1.3A rockminer fan or a wall of s1 units. noise quality isnt bad, its loud but not shrieking. A relatively loud vaccuum cleaner is the most accurate description.
OVER AND UNDER CLOCKING: Underclocking down as low as 225MHz was tried, with a linear adjustment in hashrate and temperatures reducing from 54C stock to 46C. Fan speed was reduced, but only by 600rpm, and is still too loud to conceive running in the same room as you work. Overclocking was tried to 362.5MHz and seemed to handle just fine. hashrates and temperature up slighty, fan noise stayed about the same as at 350MHz
BOARD TEMPERATURES: at stock speed and 20C ambient the readings are about 53C. With 0C intake air and 225MHz the unit reads 39C with the fan at 2880RPM. The exhaust air is far less, possibly only 10C. I think this difference will become an issue because right now the stock fans run far too fast most of the time, and I think setting higher temperature targets is possible. 2880RPM at 39C is silly, thats like 75% fan speed for about half the power usage and a fresh air intake.

so, the next step is pictures!
first, lets compare this to an antminer S1: Apart from a different controller, the unit is almost identical. The frame and heatsinks are the same (frame ends are flipped though), and the real difference is the presence of plastic side panels, which is something that was missing in the S1 but overkill in the S3. Assuming screw locations are the same you could easily have an S1->S5 upgrade kit. An interesting difference is that the screws are all spring-loaded for whatever reason. (i found that at least half the screws could be tightened about a 1/4 rotation more though)


Finally, I think the most important aspect of this review is to bring up the pros and cons of the hardware as i see it
CONS:
1) the final picture seen above shows that the reset button is not aligned with the hole in the frame. This is minor, but worth pointing out I feel. could make resetting a tad more difficult.
2) THE FAN IS LOUD!!! Seriously Bitmain, install a second fan like on the S3. I think some extra shrouding at the top could help also, just another simple piece of plastic with 4 tie-down points. I plan to install an S1 fan as a secondary soon and see how that helps.
3) undervolting the hardware is not as easy as a pencil mod or software tuning - it requires a strong 9V or adjustable power supply that few people own, and isnt necessary with the SP20
4) ITS LOUD. Im saying this again because you will not be able to run this in your living room like you could with the S3. You can hear the fan through the closed doors.

NEUTRALS:
1) It isnt fully enclosed at the top or bottom. This wont affect the majority of people and makes the unit well suited as an inexpensive miner for farms. For the home user though this might frighten off people who dont want to have things falling onto/into the miner. Theres no real risk of running this on a metal surface that i can tell, as the boards are elevated from the bottom slightly
2) DHCP - its nice to see this choose its own IP, but can make it difficult to find without an IP scanner. For the bulk user though, this saves the tedious process of setting up only one machine at a time at 192.168.1.99
3) Stock settings are enough to make the cables on my CS650M get warm. not hot by any means, but warm. A lower quality power supply might get concerningly hot cables if they are not made with thick wire.

PROS:
1) at ~0.51w/GH stock, its very power efficient.
2) Simple design. likely much cheaper to produce than the SP20, and easy to setup.
3) comes with a stripped-down beaglebone that could be repurposed or used again on future hardware versions when the S5 is no longer in use.
4) a secondary fan can easily be installed and there are holes available to screw one onto.
5) The Minerlink 'findyourminer' application has the ability to tell any specific S5 units to beep loudly and flash the LEDs - This is a fantastic idea for anyone who wants to distinguish miners from one another when dealing with DHCP changes for dozens or more of the S5

Conclusion: Its a decent miner, but in its current revision it is too loud for the home user. Underclocking could improve the volume, but it does not improve efficiency and in contrast the SP20 is a better miner if you want to underclock/undervolt for efficiency. I think Bitmain needs to revisit the drawing board for this miner, and come back with a version that has 16 chips per chain to achieve ~0.44W/GH at a similar hashrate but lower power consumption, and/or a secondary fan to keep the noise down


edit: I have a trio of SP20 units delivering tomorrow, and will follow-up this review with a better comparison of the two units

$60,000 MOQ for the bulk S3+ units is insane.

make a pack of 25 units at $125 each and ill bite.

it likely would be 1.6TH/800W as 800W was about the amount of heat the C1 could handle. 2.2TH/1.1kW would likely be too hot

16awg if you plan to push the unit past 1.2TH. Must be good quality wire if you want to push past 1.5TH

yeah, there is a LOT of 1.2W asicminer chip-based gear that's in its last days at these prices. Shortly after are the thousands of S2 units that are mining right now at 1w/GH. From there the SP10 can go to about 0.8w/GH so wont retire until the S3 hardware has to be clocked back (still 4 months away at these prices)

Looks like my order went through italy and UK on its route to canada
S5 will be in my hands first thing tomorrow morning, and hopefully the Sp20 units will arrive in the afternoon or wednesday! Looking forwards to playing with both and choosing a winner (SP20 looks like a winner on technical prowess, but the S5 may be cheaper to build

at >560W its absolutely neessary to use all 4 I think, or have a high-end PSU, as 280W over a single PCIe cable will burn up any 18awg wires, and likely even get 16awg wiring warm