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
