Athlon 64 3400 vs Opteron 148

[Grumble]

As far as I can tell, the Athlon 64 3400 and the Opteron 148 are quite 
similar. They both run at 2.2 GHz, and both have a 1 MB L2 cache.

The two (minor) differences are:

   Registered vs Unbuffered RAM
   Dual-Channel vs Single-Channel memory controller

I have access to a Mobile Athlon 64 3400:

processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 4
model name      : AMD Athlon(tm) 64 Processor 3400+
stepping        : 8
cpu MHz         : 2200.137
cache size      : 1024 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge 
mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx mmxext lm 
3dnowext 3dnow
bogomips        : 4336.64
TLB size        : 1088 4K pages
clflush size    : 64
address sizes   : 40 bits physical, 48 bits virtual
power management: ts fid vid ttp


SPEC CINT2000 Result for AMD's Opteron 148:
http://www.specbench.org/osg/cpu2000/results/res2003q4/cpu2000-20031117-02631.html

So far, I have only run mcf.

http://www.spec.org/cpu2000/CINT2000/181.mcf/docs/181.mcf.html

I am disappointed because my results are worse than AMD's. On the 
Opteron, mcf base took 250 seconds to complete. On the Athlon 64, mcf 
base took 316 seconds (26.4% slower) to complete.

I used gcc version 3.2.3 20030502 (Red Hat Linux 3.2.3-24) while AMD 
used SuSE gcc 3.3.1 compiler (from SuSE Linux 9.0).

What could explain the large difference? Did gcc improve that much 
between 3.2 and 3.3? I've read that registered RAM is actually slower 
than unbuffered RAM. Would the dual-channel help?

SPEC's mcf run requires 190 MB of memory.

http://www.spec.org/cpu2000/analysis/memory/

-- 
Regards, Grumble