Hi all,
Have you ever wanted to build a very capable computer to support science that is on the other hand side quite cheap to buy and re uses hardware that has been on the market for a long time ? There is a good opportunity out there for exactly doing that and additionally you can even earn gridcoins for that computation in exchange.
In this series of articles i will exactly do that, from the basics and the shopping list, the building and installing on to the crunching :)
But lets start with the basics first.
The Basics
The key to all this is called FP64. GPUs are generally very good at doing math, the precision within that mathematics can be set by the needs of the programmer. FP64 hereby specifies double precision, FP32 being the single and FP16 half precision.
Why is this important ?
Game development is more about FP32 and nowadays also a lot about FP16 calculations, therefore the designers of graphic cards (for the consumer market) are more into optimizing this than the FP64 power.
The outcome of this can be seen in the following table:
(GFlops means Giga Floating Point Operations per Second = 10^9 Flops, the more the better )
| Graphic card | Chipset | FP64 GFlops | FP32 GFlops | Year |
|---|---|---|---|---|
| Radeon 6970 | Cayman XT | 675 | 2703 | 2010 |
| Radeon 7870 Ghz Edtion | Pitcairn XT | 160 | 2560 | 2012 |
| Radeon 7870 XT | Tahiti LE | 749 | 2995 | 2012 |
| Radeon 7950 | Tahiti PRO2/PRO | 761 | 3046 | 2012 |
| Radeon 7970 | Tahiti XT | 947 | 3788 | 2012 |
| Radeon 7970 Ghz Edition | Tahiti XT2 | 1075 | 4300 | 2012 |
| Radeon 7990 | New Zealand | 1894 | 8200 | 2013 |
| Radeon R9 270x | Pitcairn XT | 160 | 2560 | 2013 |
| Radeon R9 390 | Hawaii Pro | 640 | 5120 | 2015 |
| Radeon R9 Fury X | Fiji XT | 537 | 8601 | 2015 |
| Radeon RX 480 | Ellesmere XT | 323 | 5161 | 2016 |
| RX Vega 56 | Vega 10 | 659 | 10544 | 2017 |
| RX Vega 64 | Vega 10 | 792 | 12665 | 2017 |
| Nvidia GTX1050ti | GP107-400-A1 | 66 | 2123 | 2016 |
| Nvidia GTX1060 | GP106-400-A1 | 137 | 4372 | 2016 |
| Nvidia GTX1070 | GP104-200-A1 | 202 | 6463 | 2016 |
| Nvidia GTX1080ti | GP102-350-K1-A1 | 354 | 11340 | 2017 |
There are some very remarkable things to be seen here. First of old Radeon Cards like the 7970 or even the 7870 XT are superior to even the GTX 1080ti in terms of FP64. Even the 6970 with the Cayman XT Chip is almost doubling the FP64 performance of a 1080ti. What also can be seen that in terms of performance increase over the years there was a lot movement, just not in FP64. The AMD cards are no better, the brand new Vega 64 is inferior to an old 7970.
What does that mean ? Are those cards really faster ?
Well there is no short answer to that, but in this specific field the answer is clearly yes. In a lot of other topics like memory bandwith, FP32 calculations, in short in all relevant things for gaming the answer is clearly no.
Ok but for what do we need this FP64 power ?
This is where the fun starts, there are scientific projects that require this double precision calculations. Milkyway@home for instance is such a project. This project uses the FP64 calculations to create a highly accurate three dimensional model of the Milky Way galaxy.
The shopping List
This all got me thinking and i came up with a shopping list for a 4 GPU crunching machine (should yield somewhere >150 mag easily).
This is just an idea, for sure the hardware can differ if you want to build such a thing for yourself. I took the Asus Board because i already have a few of them running and they are solid as a rock :) and on the other hand brings enough PCIe ports to connect the GPUs to. Iam not yet fixed in what GPUs i want to have, 7970 would be fine but 7950 or 7870XT would also do. Only in the PSU i will make no compromise, i want to have a stable new one, i wont trust in something used.
I will try Ebay and other sources of old hardware, lets see what i can get there. Maybe there is also a price drop with the new Vega Cards out, altough i dont really believe in that, there are just so few shipped ...
Shopping
I will start the shopping now, once it is concluded iam going to follow this up with the next chapter :)
If you want to know more about Gridcoin please take a look here:
Gridcoin: Gridcoin Website
If you want to know more about FP64 crunching in specific, please look into the posts from 
Example on Vortacs posts for GPUs: GPU Mining 6
