My new computer
John Nunn
I like to keep my computer hardware up to date, and my basic rule of thumb
is that when it is possible to have a system which is twice as fast as my current
system, then it is time for an upgrade. Normally, I do this by replacing the
motherboard and processor within an existing computer, which is a relatively
cheap method of improving performance. It also has the advantage that the data
on the computer does not need to be transferred to a new system.
However, this time I decided to build a new computer completely from scratch.
Why not just buy a computer, you might ask? There are two reasons why I preferred
the do-it-yourself route.
The first is that the system I intended to build would be a bit special, and
not an off-the-shelf product. Of course, if money is not taken into consideration
then you can buy virtually anything ready-made, but a quick check showed that
my intended system would cost too much if bought this way. The second reason
is that I have invariably been disappointed with complete systems I have bought.
My worst experience was relatively recent. I bought a complete system from a
well-known UK company, and to begin with everything seemed OK. Indeed, if all
you did was run Microsoft Office then you would probably never realise that
there was any problem with the machine. But if you set Fritz to analyse a position
for, say, 12 hours, then there was about a 50-50 chance that it would crash
during this period. Obviously this is unacceptable. It would also sometimes
crash when running leading-edge video games perhaps about once every two hours.
The highly intermittent nature of the problem made it hard to prove that there
was anything wrong with the system, and in fact I never did manage to get the
company involved (which had appalling customer support) to accept that the machine
was faulty. My suspicion is that such companies, which often operate on very
low profit margins, scour the world for the cheapest possible components in
order to save a few pounds. The fact that these components might be slightly
sub-standard and become unreliable under stress is probably of little concern
to them. If you are building your own machine, you can of course choose to pay
a small premium in order to obtain higher quality components.
In my opinion, reliability is the number one criterion for a computer. All
else, including to some extent performance, is secondary. This applies particularly
if you are using the computer for business purposes. What level of reliability
is acceptable? Here you have to distinguish between an individual application
crashing and the whole computer crashing, so that a reboot is required. There
is little you can do about the first of these. A poorly written application
will crash whatever hardware and operating system is being used, but the key
point here is that the operating system should close the dead application without
any fuss, and then continue running as normal. However, the second type of crash
is much more serious as a reboot will lose you any unsaved work in other applications
which are running, and may cause corruption to files on the hard disc.
I would say that for a computer running eight hours a day, one system crash
a month is probably the limit of acceptability and there is no reason why this
should not be achieved (both my current main systems have at least this level
of reliability). It's probably not possible to achieve such a level using Windows
98, because of the tendency for one crashing application to bring the whole
system down; this implies that Windows 2000 and Windows XP are the only viable
versions of Windows. Personally, I prefer the former but I accept that this
is to some extent a matter of taste.
After reviewing the various possibilities, I decided on the following basic
components:
- Supermicro X5DAL-G dual Xeon motherboard
- Two 2.8 GHz Xeon processors
- 200 GB hard disc
- 1 GB ECC Registered RAM
- Supermicro SC762-420 case
Of course, a few other miscellaneous components are necessary, but I could
save on most of these by recycling them from earlier machines. As this computer
was to be focussed on chess, video performance was not important.
The above picture shows all the components ready for assembly. I would like
to thank my brother David for his assistance in assembling the computer (in
truth, he did almost all the work...). The tricky bit is putting the processors
on the motherboard:
This picture shows the motherboard ready for the processors. The sockets for
the Xeons are on the top right; the memory slots are to bottom right. The heatsinks
for the Xeons are so massive that they have to be attached to reinforcing plates
which are mounted under the motherboard. Presumably the motherboard would simply
bend if this were not done.
Both Xeons are in their sockets and the heatsink has been attached to the one
on the right. Before attaching the heatsink you should squirt some thermal compound
on top of the Xeon. Intel thoughtfully provides a hypodermic with the Xeon for
precisely this purpose.
Here both heatsinks have been attached and the cooling fans mounted on top.
The next step is to mount the motherboard in the case. For a dual Xeon system,
it is a good idea to use a case specifically designed for the purpose, as the
power and cooling demands of the Xeons are considerable.
The motherboard has now been mounted in the case. You can see the 1 GB of RAM
on the right side of the motherboard.
There isn't much more to say as all the other components are standard. The
above photograph shows the inside of the case with everything installed and
ready to switch on.
With home-built computers, there is usually some small problem to be resolved
at switch-on time, but on this occasion everything worked immediately and it
was only necessary to put the operating system CD-ROM in the drive and wait
for it to install itself.
Of course, you're probably all waiting to know how the chess is. One of the
problems with currently available processors is that they are not particularly
well suited to the integer calculations used for chess. A Pentium 4 will be
slower at chess than a Pentium 3 of an equivalent clock speed. The upshot is
that although I was switching from a dual-processor 1.2 GHz Pentium 3 machine
to a dual-processor 2.8 GHz Xeon machine, the new computer wasn't 2.2 times
as fast, which is what you would expect from the clock speeds. Instead, it turned
out to be about 1.7 times as fast at chess. FritzMark, which only uses one processor,
gives a value of 1276 on the new machine. Since the second processor generally
adds a factor of 1.7 to the speed, you can say that the estimated FritzMark
of the machine is about 2170.
A typical middlegame position with Deep Fritz 7 gave about 2.15 million nodes/sec
(Mn/S) while Deep Junior 7 gave about 2.55 Mn/S. Here is some analysis:
It didnt take long to find a missed win by Adams against Spraggett at
the Elista Olympiad in 1998. The key point here is finding the move 27 h3 which
is the move that makes the combination work. Once the machine displays this
move, you can say that it has found the combination. As you can
see from the screenshot, it took Deep Fritz 7 running at 2.608 Mn/S just 2 seconds
to find the win. It makes a big difference to the time how many lines of analysis
you show; here it is two.
Here is a famous combination (Zuckertort-Blackburn, London 1883). The position
is normally given after 26 gxh7+ Kh8 27 d5+ e5, but the computer found 28 Qb4!!
so quickly that I couldnt accurately measure the time. Therefore I set
it back two moves and started it running. The evaluation suddenly jumps from
about equal to +5 when it sees that 28 Qb4!! is winning. Time taken: 6 seconds
(you cant see the time in this screenshot, but it really was six seconds!)
at 2.313 Mn/S.
All in all, the new computer seems quite satisfactory, although changes in
processor design mean that chess comes off second best relative to other types
of application, so perhaps the performance isn't quite what I might have hoped
for.
I should add a couple of words of warning. Firstly, if you like quiet computers,
this sort of machine is not for you. The massive fans needed to take the heat
out of the case are quite noisy. Secondly, you shouldn't attempt to build you
own computer unless you are confident of your ability to do so. Obviously, if
you do it, then it is entirely at your own risk.