$84 savings ($14 per OC'ed machine) per annum in the context of bitcoin mining can be construed as splitting hairs when you factor in difficulty increase (over the projected year) and daily earnings' variations (pool luck) given a constant hashing rate.
But hey, even a $1 saving is exactly that, and pool luck can be to your favour!

Why update the firmaware?
After changing the speed all you had to do is reboot.
Now you have updated the firmaware, you'll have to do it all over again, only this time you need to change a different file as the new firmware has been noted for reverting the OC.

Slush's pool luck has also been down A LOT in the last couple of days.
Even looking at P2Pool, does not look like they've had "out of the ordinary" luck in the last 48-72 hours, albeit a couple of quickfire blocks a day or so ago.
So looks like it is grim all round ....!

It is strange how the DiffR number differs widely (in shape and size) depending on which pool you mine at and which hardware you deploy.
The S3 for example does not show a best share on some pools whereas the S1 does, in the same breath, the S3 increments DiffR in multiples of 32 on some pools (in the case of ghash DiffR equates to stales) whereas I'd have expected it to be singulars as is on slush.

Which leads me to believe that some stats on the S3 are massaged thus the HW error percentage is ..... who knows!?

I've always wanted to clarify this, so here goes.
What exactly does DiffR represent? I assumed this represented the number of rejected shares at the current Diff, but its rate of increase seems to be (at times) the size of the rejected share. If that, would that not throw the calculation off?

I did not have any concern about damaging the unit, rather damaging the PSU. As mentioned, it is a 550 watt psu and since I could not measure the "wall" wattage at the overclocked speeds, I was worried I may be stretching the PSU beyond its reasonable capacity. Mind you, I have been running my S3 at the higher clock speed since and still hashing away without much ceremony!

The only way that I know of how to tell what batch it is is either buying it yourself from bitmain or asking the person who bought it.


Yep, you ARE having an issue there with the HW errors. Too high for an S3 (and one running at stock frequency at that)!
1. Are you sure you are powering it up adequately? If that, do a power recycle (there may have been a power spike since you turned it on) and see if the errors settle.
2. I have noticed that the HW errors general % varies from pool to pool. I did not think this to be a contributing factor, but I have observed on my S3's that it may indeed be a factor, thus, try hashing on another pool for several hours. That being said, your error rate is far higher than what I'd attribute to a pool.

Spill the beans on this one then .... $110 seems a bit steep, does your mod entail scrapping the S1 control boards?

Your PSU seems fine, though since I do not know how it sends out its power, I can not be totally sure. If you want to go down the server PSU end, look at the one I used as stated in the first post. Bear in mind that you'll have to "make" the cables for it and will have to do some soldering (not plug and play as the one you have!).

That looks like its capable of running 2 slightly underclocked S3's, so should not be an issue running one. However, I do not know enough about how these desktop PSU's pump out their power. I'd suggest you use all 4 PCIe connection if you have not been doing so. If you still get such high errors, then it may be just a case of your unit not being able to overclock well.

How are you powering your S3, i.e what is your PSU's power rating and how are you connecting it to the S3? Note that though I used just 2 PCIe connections for my test, I was using a server PSU that has 3 12V rails each pumping out at least 15A, so for my case, each +ve line in each PCIe plug can deliver 12V @ 7.5 Amps.

Either will do

What are the specs for the rig you intend to write on building?
For under $500, you can get 2 S3's with a combined stock hash-rate of 880 Gh/s @ 720 watts (plug and play!)
Does it make sense ... ? Money sense ...? Makers' sense ... ?

I thought that you may be under-powering your S3 and suspected your lack of increased hash-rate was masked in the HW errors (as opposed to X on the chips). however, 850 watts is more than adequate to overclock an S3, and as you can see from my results, I only used a 550 watt PSU with just 2 PCIe connections!
Well well, looks like you drew the short straw with your unit, but at least you got the voucher to sweeten that!

I believe the earlier S3's do not overclock as easily as the later batches (and thats why the first batch received discount vouchers I believe).
Aside from that, you mention you are not getting any chips marked with X but you have not mentioned whether your hardware errors. Are you sure you are powering the S3 adequately and what are the hardware errors?

I did a similar test, but on a batch 6 S3 and posted the results here: https://bitcointalk.org/index.php?topic=750220.0

That is a very good question and there are a couple of ways you can do this.
1. Buy a couple of 8 pin PCIe to 6 pin PCIe cables. These MUST have all the 6 connections to the 6 pin end populated. (I am informed these are usually called nVidia graphics cards power cables, but I can not confirm that).
From here it is up to you what you prefer to do. You can either have your 15A cables from the PSU feeding into a male 8 pin PCIe which you then connect to your cables above OR you can slice off the 8 pin end from your cables, and using an inline connection joiner (from a connection strip rated for at least 15A and available for around 2 GBP for a set of 12), connect your sliced now cable to the PSU cables.

DO NOT buy the 4 pin molex to 6 pin PCIe adapters on the net as they will most likely not be able to handle the amperage. They also do not have all the wires to the 6 pin populated.

2. You can actually buy the 6 pin PCIe housings and the female crimps that go into them from the web and make them up yourself using the slicing method above. For wires, get those that can handle 7 amps (thus every 6 pin PCIe connector can feed 21 amps to the blade). Do not be put off with the crimping as you can do this easily using a pair of sharp pointed pliers.

NOTE: With the three rail PSU, use one rail to power each blade independently with the third one shared between the two. i.e the independent rail will power two ports of the 6 pin PCIe (15A /2 = 7.5) and to share the common rail, simply join these with a length of the 15A wire.

No worries, just make sure you have your solder iron and 15A (or over) cables ready for when the supply arrives!
I've posted my overclocking tests for an S3 with a 550 watt Dell server PSU here: https://bitcointalk.org/index.php?topic=750220.0

The easiest way to get the specs is to read them from the sticker on the PSU. So it follows, google the PSU, click images and find an image you can read. Another option is the dell website or even better, find a seller on ebay and they'll most likely have an image of the item they are selling!
Happy hashing.

Come off it! Where did YOU get yours from? In any case, simple maths will tell you 670 watts from 12V needs 55.83 A
I run my S3's off 550 watt Dell server PSU's overclocked to 262.5M, so I know for sure I can run an S3 on 670 watt PSU and not even need to have the PSU cooling fan running at the max.
Honestly, do some research .... thats what google is there for!

Are you speaking from a position of knowledge or are you speculating?
The linked PSU has 3 12V rails with more than enough amperage in the rails combined to power 2 S3's running slightly underclocked, and DEFINITELY to power a single S3 overclocked to the max.

Ffrom the specs: Output Max. Load 12V 54.4A