I have a 512MB RAM 20GB HDD 1st generation rackspace cloud server the result of cat /proc/cpuinfo shows 4 processors.

processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 16
model           : 4
model name      : Quad-Core AMD Opteron(tm) Processor 2374 HE
stepping        : 2
cpu MHz         : 88885.885
cache size      : 512 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow constant_tsc rep_good nonstop_tsc pni cx16 popcnt lahf_lm cmp_legacy extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch
bogomips        : 4400.17
TLB size        : 1024 4K pages
clflush size    : 64
cache_alignment : 64
address sizes   : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

processor       : 1
vendor_id       : AuthenticAMD
cpu family      : 16
model           : 4
model name      : Quad-Core AMD Opteron(tm) Processor 2374 HE
stepping        : 2
cpu MHz         : 88885.885
cache size      : 512 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow constant_tsc rep_good nonstop_tsc pni cx16 popcnt lahf_lm cmp_legacy extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch
bogomips        : 4400.17
TLB size        : 1024 4K pages
clflush size    : 64
cache_alignment : 64
address sizes   : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

processor       : 2
vendor_id       : AuthenticAMD
cpu family      : 16
model           : 4
model name      : Quad-Core AMD Opteron(tm) Processor 2374 HE
stepping        : 2
cpu MHz         : 88885.885
cache size      : 512 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow constant_tsc rep_good nonstop_tsc pni cx16 popcnt lahf_lm cmp_legacy extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch
bogomips        : 4400.17
TLB size        : 1024 4K pages
clflush size    : 64
cache_alignment : 64
address sizes   : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

processor       : 3
vendor_id       : AuthenticAMD
cpu family      : 16
model           : 4
model name      : Quad-Core AMD Opteron(tm) Processor 2374 HE
stepping        : 2
cpu MHz         : 88885.885
cache size      : 512 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow constant_tsc rep_good nonstop_tsc pni cx16 popcnt lahf_lm cmp_legacy extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch
bogomips        : 4400.17
TLB size        : 1024 4K pages
clflush size    : 64
cache_alignment : 64
address sizes   : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

The new OpenCloud Servers report this for cpu:

processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 16
model           : 8
model name      : AMD Opteron(tm) Processor 4170 HE
stepping        : 1
cpu MHz         : 2100.056
cache size      : 512 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow up rep_good pni cx16 popcnt hypervisor lahf_lm cmp_legacy extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch
bogomips        : 4200.11
TLB size        : 1024 4K pages
clflush size    : 64
cache_alignment : 64
address sizes   : 48 bits physical, 48 bits virtual
power management: ts ttp tm stc 100mhzsteps hwpstate

So going by the above the CPU specs seems to be downgraded from the 1st generation.

However I noticed that the pricing for my 1st generation server is $0.03/hr ($21.90/mo) and the equivalent Opencloud offering is $0.022/hr ($16.06/mo) so the reduction in performance is allowed for in the price. So they haven't done what confectionery manufacturers do and reduce the pack size while keeping the price the same.

But you can't add an extra hard disk drive on the 1st generation server as you can with Opencloud so if you had run out of space on the 20GB volume you had to resize up to the 1GB RAM/40GB HDD at double the price. I belief the opencloud offering will be more flexible.

So I'm not sure if I'm wanting to upgrade just at the moment... especially with my 1st gen servers uptime / reliability being what it is:

 02:15:38 up 305 days, 23:16,  2 users,  load average: 0.07, 0.03, 0.00

REF:  http://seancombinator.com/rackspace-firstgen-vs-opencloud