What is the best way to compare PCs? (HP DL385 G7)

I have 3 HP DL385 G7 and I would like to compare them and see what is causing the differences between hash rates.

All are...
HP DL385 G7
Win10
8G Ram (4x2G 2Rx8 PC3-10600R-9-10-B0)
xmr-stak 2.4.3 3272f16
no other cards

Machine #1 - 6234x2 - last config line - { "low_power_mode" : true, "no_prefetch" : false, "affine_to_cpu" : 22 },
HASHRATE REPORT - CPU -
| ID | 10s | 60s | 15m | ID | 10s | 60s | 15m |
| 0 | 63.7 | 63.2 | (na) | 1 | 63.6 | 63.3 | (na) |
| 2 | 63.7 | 63.2 | (na) | 3 | 64.0 | 63.8 | (na) |
| 4 | 64.0 | 63.8 | (na) | 5 | 64.0 | 63.7 | (na) |
| 6 | 64.3 | 63.2 | (na) | 7 | 64.2 | 63.2 | (na) |
| 8 | 64.1 | 63.0 | (na) | 9 | 63.9 | 64.2 | (na) |
| 10 | 63.9 | 64.1 | (na) | 11 | 63.9 | 63.9 | (na) |
Totals (CPU): 767.1 762.6 0.0 H/s
-----------------------------------------------------------------
Totals (ALL): 767.1 762.6 0.0 H/s
Highest: 771.4 H/s
-----------------------------------------------------------------

Machine #2 - 6238x2 - last config line - {"low_power_mode" : true, "no_prefetch" : false, "affine_to_cpu" : 22 },
| ID | 10s | 60s | 15m | ID | 10s | 60s | 15m |
| 0 | 65.6 | 65.7 | (na) | 1 | 65.5 | 65.8 | (na) |
| 2 | 65.2 | 65.6 | (na) | 3 | 66.9 | 66.9 | (na) |
| 4 | 66.8 | 66.8 | (na) | 5 | 66.7 | 66.7 | (na) |
| 6 | 67.0 | 66.8 | (na) | 7 | 66.9 | 66.7 | (na) |
| 8 | 66.8 | 66.7 | (na) | 9 | 66.6 | 66.5 | (na) |
| 10 | 66.4 | 66.4 | (na) | 11 | 66.1 | 66.1 | (na) |
Totals (CPU): 796.6 796.7 0.0 H/s
-----------------------------------------------------------------
Totals (ALL): 796.6 796.7 0.0 H/s
Highest: 803.2 H/s
-----------------------------------------------------------------

Machine #3 - 6272x2 - ran it with low_power_mode" : false and low_power_mode" : true
last config line - { "low_power_mode" : true, "no_prefetch" : false, "affine_to_cpu" : 30 },
| ID | 10s | 60s | 15m | ID | 10s | 60s | 15m |
| 0 | 40.8 | 40.3 | (na) | 1 | 40.9 | 40.5 | (na) |
| 2 | 40.8 | 40.5 | (na) | 3 | 40.6 | 40.3 | (na) |
| 4 | 41.3 | 41.6 | (na) | 5 | 41.4 | 41.9 | (na) |
| 6 | 41.4 | 41.8 | (na) | 7 | 41.2 | 41.8 | (na) |
| 8 | 41.3 | 41.2 | (na) | 9 | 41.3 | 41.3 | (na) |
| 10 | 41.3 | 41.3 | (na) | 11 | 40.9 | 41.2 | (na) |
| 12 | 41.4 | 41.8 | (na) | 13 | 41.3 | 41.8 | (na) |
| 14 | 41.4 | 42.0 | (na) | 15 | 40.9 | 41.6 | (na) |
Totals (CPU): 658.3 660.9 0.0 H/s
-----------------------------------------------------------------
Totals (ALL): 658.3 660.9 0.0 H/s
Highest: 671.1 H/s
-----------------------------------------------------------------

last config line - { "low_power_mode" : false, "no_prefetch" : false, "affine_to_cpu" : 30 },
| ID | 10s | 60s | 15m | ID | 10s | 60s | 15m |
| 0 | 46.0 | (na) | (na) | 1 | 46.3 | (na) | (na) |
| 2 | 46.3 | (na) | (na) | 3 | 46.2 | (na) | (na) |
| 4 | 46.3 | (na) | (na) | 5 | 46.2 | (na) | (na) |
| 6 | 46.2 | (na) | (na) | 7 | 46.1 | (na) | (na) |
| 8 | 46.5 | (na) | (na) | 9 | 46.3 | (na) | (na) |
| 10 | 46.4 | (na) | (na) | 11 | 46.5 | (na) | (na) |
| 12 | 46.0 | (na) | (na) | 13 | 46.1 | (na) | (na) |
| 14 | 46.3 | (na) | (na) | 15 | 46.4 | (na) | (na) |
Totals (CPU): 740.2 0.0 0.0 H/s
-----------------------------------------------------------------
Totals (ALL): 740.2 0.0 0.0 H/s
Highest: 743.3 H/s
-----------------------------------------------------------------

I want to compare machines #1 or #2 to machine #3 so I can figure out why the 6234 and 6238 are hashing at a higher rate than the 6272. What is the best way to approach this?

Thanks!