July 2020 5k Budget Multi GPU Build
#1
Hello community,

After years of pitching, I have finally secured a modest budget (5K) to build a hashcat rig for my internal security team to audit with.  

I am dying to get started but all the hardware specs I'd originally put together based on various publicly discussed builds are way, way out of date, and it seems the field has grown even more confused since then.

Rather than spending another three months digging around the interwebs talking to burnt out coinheads and zealot gamers, I figured I'd go straight to the source and look here.  I've found some great info in this forum and also some concerning gotchas that have me questioning some of my original assumptions, so maybe I should just start from scratch.

If you had 5K to spend building a haschcat rig, what exactly would you put together? MB/CPU/GPUs/Cooling?

For GPU's - My instinct was to spend half the budget on 2X NVIDIA GTX 2080 TI Founder's Edition cards.  That seems like it would still get me benchmark results as good as the 4 cards I was considering when I first put together this proposal, and for less total power consumption/noise.. but reading around here, lately those may have fallen out of favor for cooling reasons?

CPU / Motherboard combo.  Intel/AMD Xenon, dual procs?  I'm game for anything that gets me in under budget, it would be a slight bonus if the machine could also have utility in a lab scenario when it is not cracking.  And to be fair I don't expect to be pushing it for more than 48 or 72 hours at a time if that factors into anyone's thinking.

Any guidance would be appreciated.  Any known exact build with decent performance would be a godsend.

Thanks!

Alias
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#2
There are some open questions that come to my mind:

1. Do you plan to put this rig into a server cabinet where noise is irrelevant or do you want to put it into a room where people are working? This mainly impacts choices for chassis and cooling.

2. Do you want to have an option to upgrade this rig (e.g. up to 4 GPUs in total) or do you want to stick with 2? This is critical for the choice of the platform. For 2 GPUs, any consumer platform (AM4/LGA1151/1200) is sufficient. For up to 4 GPUs, something like old Threadripper (X399) or Intels Core X-Series (X299) works well. Some Intel boards even allow up to 7 GPUs, but will require risers due to space limitations.

Dual Xeons are definitely overkill for a 5k budget.
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#3
The GTX 2080 Ti is a good chip but don't buy a FE. You should get OEM-design blower fans instead.

Important questions though: what hash types are you mainly going to attack and do you need options for upgrades in the future?

Depending on your answers the recommendations for CPU/MB can vastly differ. For example you need to consider the number of available PCIe lanes and maximum RAM (which should be >= VRAM). If you're mainly going to crack stuff like bcrypt or scrypt you would be much better off with fast CPUs instead of GPUs.
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#4
Thanks for your interest in my question:

(07-18-2020, 12:30 PM)NoReply Wrote: 1. Do you plan to put this rig into a server cabinet where noise is irrelevant or do you want to put it into a room where people are working? This mainly impacts choices for chassis and cooling.

This will probably wind up in my shared office, so noise would be a consideration.  I haven't built PC's since water cooling became a thing, so I'm not easily able to guess how much noise it would reduce, but very happy to go that route if it makes cohabitating with the rig possible.  Ideally, if it ran cool and quiet up until it started cracking, that would be fine, since I imagine most of the heavy lifting will be done over weekends.  The least desirable situation is one where it is loud even when idling, or just being used for other research.

2. Do you want to have an option to upgrade this rig (e.g. up to 4 GPUs in total) or do you want to stick with 2? This is critical for the choice of the platform. For 2 GPUs, any consumer platform (AM4/LGA1151/1200) is sufficient. For up to 4 GPUs, something like old Threadripper (X399) or Intels Core X-Series (X299) works well. Some Intel boards even allow up to 7 GPUs, but will require risers due to space limitations.

Upgrading the rig in the future is a possibility,  It is unlikely that we would go beyond 2 GPU's but in that scenario, we'd just as easily be able to swap motherboards and processors if necessary to add more cards, or even cases.  Once we got into more than 2 GPU's this thing would probably go into a rack anyway, so that would basically be a new build with just the GPU's surviving the cut.

Dual Xeons are definitely overkill for a 5k budget.

(07-18-2020, 01:24 PM)undeath Wrote: The GTX 2080 Ti is a good chip but don't buy a FE. You should get OEM-design blower fans instead.

Alas, I have heard that before, but I'm not 100% sure how to judge a good OEM fan, and there are so many non FE cards to choose from, this is where I can get quickly lost.  Do you know of any specific cards you can recommend?

Important questions though: what hash types are you mainly going to attack and do you need options for upgrades in the future?

This is mainly for cracking the NTLM hashes of around 6000 users and service accounts.

The ability to move up to 4 cards would be nice in the future, but if the best overall CPU/Motherboard/Coolling situation limits me to two cards to start, then I can probably swap out the components later to get to a 4 card machine.

Depending on your answers the recommendations for CPU/MB can vastly differ. For example you need to consider the number of available PCIe lanes and maximum RAM (which should be >= VRAM). If you're mainly going to crack stuff like bcrypt or scrypt you would be much better off with fast CPUs instead of GPUs.

This feedback has been great so far, happy to answer more questions if it helps to narrow things down further. 
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#5
You want blower style cards, because they support a linear front-to-back airflow through your chassis, which is extremely important, when you put more than 2 cards into your rig. Stacking cards with axial fans not a good idea in a closed chassis, because the hot air is not properly pushed out of the back of the chassis.

The goto card to recommend is the EVGA 2080 Ti Gaming, which has a blower style fan. Its cooling design is leaning towards the one of Pascal FE cards, which was probably one of the best designs, if you wanted to stack them. Unfortunately, it is kinda hard to find some of them, which are in stock.

Based on your answers, here is an example configuration I came up with. If you have any questions on the choices, feel free to ask. It might be worth it to swap out the built-in chassis fans for some more powerful ones.

https://www.newegg.com/mr/7DD8900107495C...EA09FA66A3
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#6
Thanks a ton for the thought you put into below and the link.  I used it as a base and made a few tweaks.  I'll come back and post results once I get it built.


(07-19-2020, 12:57 PM)NoReply Wrote: You want blower style cards, because they support a linear front-to-back airflow through your chassis, which is extremely important, when you put more than 2 cards into your rig. Stacking cards with axial fans not a good idea in a closed chassis, because the hot air is not properly pushed out of the back of the chassis.

The goto card to recommend is the EVGA 2080 Ti Gaming, which has a blower style fan. Its cooling design is leaning towards the one of Pascal FE cards, which was probably one of the best designs, if you wanted to stack them. Unfortunately, it is kinda hard to find some of them, which are in stock.

Based on your answers, here is an example configuration I came up with. If you have any questions on the choices, feel free to ask. It might be worth it to swap out the built-in chassis fans for some more powerful ones.

https://www.newegg.com/mr/7DD8900107495C...EA09FA66A3
Reply