Hotbox v1.2 dual GTX 1070 mining rig

skullbringer · July 8, 2017

Long time no see, but I thought I wanted to share my progress of me getting into mining.

As you might notice from the v1.2, this is not the original configuration, but I will get to that later.

Specs:

Intel Core i7-4930k
Asus Rampage IV BE
Corsair H80
three Noiseblocker NB eloop B12-4's
Corsair RM1000
some Seagate 1TB HDD
two MSI GTX 1070 Armor 8G's
some random 15-year old case which housed my first ever gaming pc back in the day

All of these parts I had lying around from older builds, so I might as well put them to work mining, instead of sitting on a shelf. Apart from the GPUs which I managed to get for a reasonable deal NEW from Alternate.de

This is the most standard atx case you could have probably gotten 15 years ago, just cheapo thin metal, mostly riveted, with a plastic font cover, perfect for modding. So I just removed the front plastic cover and all the pre stamped metal 5.25 inch cutouts for air intakes. With v1.1 I also added the fan in the side panel to help airflow, originally the side panel was just solid all the way. Also all the fan mounts are for 80mm fans. I guess 120mm was not a thing back then, so fan mounting was creative. If you need a Windows XP license, there is one for you on the side panel xD.

Opening up the side panel, you can see the crowded interior, which was never meant to house this much and powerful hardware. In the back you can see the for me useless 80mm fan mounts. In Hotbox v1 I had a fan there, thinking it would help exhaust hot air, but placing it next to the gpus on the side panel was much more effective, so the psu fan does all the exhaust for the cpu area.

Also you can see the fan directly in front of the gpus to push as much air towards them as possible, being circulated by the gpu coolers and then exhausted by the side panel fan. This setup actually allows the gpus to run without throttling in this very confined space, whereas in v1 without the side panel fan, the gpus would be constantly at 93°C and throttling down.

From here you can see the H80 with its fan just sitting casually in the 3 5.25" bays pulling in fresh air from the front. The cpu is running at stock, as no cpu power is needed and hovers around 50°C idle.

You can also see that the HDD is pushed as far to the front as possible to make room for the motherboard. Since the R4BE is eATX, it barely even fits along side the hdd cage. The result is the HDD is poking out through the front 3.5" floppy bay. lol

Speaking of the HDD cage, you can see the traces of my modding efforts when making room for those GPUs. Below the now installed HDD would normally be another 5 bays, which I drilled out the bottom rivets and then cut out with a Dremel to allow for these beefy GPU coolers.

Finally, the heart of Hotbox, the two MSI GTX 1070 Armor 8G's. I got them from Alternate.de for 450 Euros per piece with 30 Euros cashback each. So a pretty good deal considering they are going on Ebay used for 500+

Understandably so, they are running amazingly well and even at the constant 100% fan speed I set them to reasonably quiet. And they overclock like a beast as well:

GPU1: 2088 MHz avg. core clock, 4325 MHz memory ~ 29.5 MH/s DAG

GPU2: 2124 MHz avg. core clock, 4400 MHz memory ~ 31 MH/s DAG

The overall system power draw with this config is 440W.

Originally Hotbox v1 to v1.1 consisted of a MSI P67A-GD55 and an i5 2500k, admittedly much more reasonable in terms of power usage for a dual gpu system. With this setup, my power draw was 380W total.

But, since I wanted to add more GPU's I swapped the Sandy Bridge rig for Ivy Bridge-E, with some disappointment.

The third GPU I added in (Powercolor RX 480 8GB Red Dragon) caused so much heat and very diminished returns, making it not viable in this chassis. It barely held 1000 MHz core clock and was constantly sitting at its tjmax of 90°C. Even when pushing the two GTX 1070s down to the bottom of the motherboard with no clearance between them, and having the RX 480 on top with spare slots between it and the 1070s and a fan blowing directly at it, it would not run reliably at 100% load.

So this is what I am at for now, I am probably going to go back to spec v1.1 with P67A and 2500k with Intel stock cooler, but I am also in the process of building a mining rig out of some old slat frame. This way I should be able to run the R4BE with all its pcie slots populated with pcie usb extenders to its full potential.

Star of the show for me are definitely the two 1070's. For about 160W power usage each, you get about 30MH/s DAG, 0.3GH/s Lbry and 450H/s Equi, which is slightly more than an RX480/580. Granted, RX cards are cheaper, but they also use more power (about 220W in my testing). Considering energy costs are quite high in Germany, the more power efficient 1070s look like a more profitable solution in the long run. Unfortunately, I can not get any more of them new for now, since prices have sky rocketed even more.

But then again, who knows how long this whole mining rush is going to hold up anyways, and if investing at this point even makes sense... At least I am having fun with some projects and am hopefully able to flip the cards for a reasonable return, in case things go south..

So what do think? RX or GTX for mining? Any way I could improve Hotbox for v1.3?