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Message-ID: <20160710121416.GA2231@openwall.com>
Date: Sun, 10 Jul 2016 15:14:16 +0300
From: Solar Designer <solar@...nwall.com>
To: john-users@...ts.openwall.com
Subject: Re: best way to attack bcrypt, for me
On Wed, Jul 06, 2016 at 07:46:32PM -0400, Rich Rumble wrote:
> 2k + ease of use (aka stupid user) = ....?
Another maybe-good option is to buy some Haswell-EP or Broadwell-EP ES
(engineering sample) CPUs off eBay. They're often sold for a fraction
of the list price. Some sellers include info on what motherboard they
tested the particular CPU in, along with CPU-Z screenshots. Some are
even willing to sell a tested MB+CPU combo. These CPUs work in single-
or dual-socket motherboards/configs.
You search for these by entering specific E5-26xx model numbers (get a
list of them from Intel's website or from Wikipedia) and having your
listing sorted for price (lowest first). You may also try adding ES or
QS to your search keywords.
These are typically available from sellers in Hong Kong, China, Japan,
but recently also from some in the US and in Russia.
For example, "Intel Xeon E5-2697 v4 ES Broadwell-EP CPU 2.2GHz 18-Core
145W" is $599 from a seller in the US now ("4 available / 35 sold").
The seller also lists motherboards "that we have tested to be compatible".
You can probably fit two of those CPUs plus a dual-socket motherboard in
$2k, and you'll have some empty PCIe slots in there for further
expansion of the system.
The same seller also offers "Intel Xeon E5-2698 v4 ES Broadwell-EP CPU
2.0GHz 20-Core 135W" (also $599, similar performance) and many other CPUs
(both smaller&cheaper, and larger&pricier). When comparing these, you
take the all cores active max turbo clock rate and multiply it by the
number of cores, e.g. 2.6*18 = 46.8 vs. 2.3*20 = 46.0 for these two CPUs
(using the seller's provided max turbo clock rates, which for ES may in
fact differ from Intel's published ones). You should also consider TDP.
There are cheaper offers from international sellers, e.g. "Intel Xeon E5
2695 V3 ES 2.2Ghz 35MB 14C 28T 22nm LGA2011-3 145W QEY6 Processor" from
Hong Kong for $329.99, but if you're in the US you'll probably prefer to
buy from a seller in the US unless the performance/$ difference is large.
There are also slightly older/smaller CPUs like "Intel Xeon E5 2670 V2
ES 2.30GHz 25MB 22nm 115W 10 Core LGA2011 QDNR Processor" for around
$140 from sellers in Hong Kong. These could be more cost-effective if
you find inexpensive dual-socket motherboards and choose to build 2+
cheaper systems.
You'll need to do some more searching before you find what feels optimal
to you.
As far as I'm aware, the motherboards required for v1/v2 vs. v3/v4 are
different, whereas v1 vs. v2, and v3 vs. v4 are usually interchangeable
but may require BIOS upgrade.
Good luck!
Alexander
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