[Scip] Performance of Nehalem machine

[Anthony Presley]

Hi all!

I've tried solving an MPS problem (about 24MB in size), with 4011
variables and 65108 constraints.

In trying to benchmark scip, I installed scip on to two servers, along
with CLP (from subversion).

One machine has these characteristics: (machine1)
	(2) Xeon 5570 Nehalem CPU's @ 2.93Ghz
	24GB of RAM

The other has these: (machine2)
	(1) Xeon E5410 @ 2.33Ghz
	8GB of RAM

Neither machine is doing anything other than running scip (and whatever
background processing the kernel does).

However, in this case, when getting to say, a gap of 4724.87%, machine1
looks like this:

 time | node  | left  |LP iter| mem |mdpt |frac |vars |cons |ccons|cols
|rows |cuts |confs|strbr|  dualbound   | primalbound  |  gap   
t 0.8s|     1 |     0 |     0 |  60M|   0 |   - |2866 |  46k|  46k|   0
|   0 |   0 |   0 |   0 |      --      | 1.681391e+07 |    Inf 
 42.9s|     1 |     0 | 25711 |  82M|   0 | 353 |2866 |  46k|  46k|2866
|  46k|   0 |   0 |   0 | 3.481961e+05 | 1.681391e+07 |4728.86%
b43.3s|     1 |     0 | 26093 |  82M|   0 |   - |2866 |  46k|  46k|2866
|  46k|   0 |   0 |   0 | 3.481961e+05 | 1.680000e+07 |4724.87%

And machine2 (to get to the same gap) looks like this:

 time | node  | left  |LP iter| mem |mdpt |frac |vars |cons |ccons|cols
|rows |cuts |confs|strbr|  dualbound   | primalbound  |  gap   
t 0.7s|     1 |     0 |     0 |  60M|   0 |   - |2866 |  46k|  46k|   0
|   0 |   0 |   0 |   0 |      --      | 1.681391e+07 |    Inf 
 32.5s|     1 |     0 | 25711 |  82M|   0 | 353 |2866 |  46k|  46k|2866
|  46k|   0 |   0 |   0 | 3.481961e+05 | 1.681391e+07 |4728.86%
b32.8s|     1 |     0 | 26093 |  82M|   0 |   - |2866 |  46k|  46k|2866
|  46k|   0 |   0 |   0 | 3.481961e+05 | 1.680000e+07 |4724.87%


More specifically, the older, slower, processor solves (up to this
point) almost 10 seconds faster.

I was expecting the opposite, out of a processor that is significantly
more expensive.

Any ideas what's going on?

Both scip's were built using "make LPS=clp" and that's it.  Coin was
built using "make".

Both boxes are running an up to date CentOS 5.4

Thanks!


--
Anthony