Comparison of RAM
What is the optimal value of CL (CAS latency) ?
RAM kits with CL >= 11 or CL <= 7 are known to cause problems (kernel panics).
So, only RAM kits with CL8, CL9, CL10 are left.
CL8 kits cannot be seen anywhere. CL10 kits are reported to work good by some users.
But, even if it is true, you should still prefer CL9 kits, because they are faster than CL10 kits.
Timings of CL9 RAM: 9-9-9-X, where X is tRas.
If tRas is not specified (9-9-9), then tRas = 9*3 = 27
The smaller tRas is, the faster RAM is.
8GB (2x4GB) 1600MHz CL9 RAM comparison
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| _______________ Model ________________ | Works | tRas _ | __ Voltage | Price in $ |
| Kingston HyperX LoVo KHX16LS9P1K2/8 __ | YES _ | _ 27 _ | _ 1.35/1.5 | ___ 70 ___ |
| Corsair Vengeance CMSX8GX3M2A1600C9 __ | YES _ | _ 24 _ | ______ 1.5 | ___ 57 ___ |
| Kingston HyperX KHX1600C9S3P1K2/8G ___ | YES _ | _ 27 _ | ______ 1.5 | ___ 61 ___ |
| G.Skill F3-12800CL9D-8GBSQ ___________ | YES _ | _ 28 _ | ______ 1.5 | ___ 50 ___ |
| G.Skill F3-12800CL9D-8GBSK ___________ | YES _ | _ 28 _ | ______ 1.5 | ___ 60 ___ |
| AData XPG AXDS1600GC4G9-2 ____________ | NO __ | _ 24 _ | _ 1.35/1.5 | ___ 65 ___ |
| Kingston HyperX KHX1600C9S3K2/8GX ____ | NO __ | _ 27 _ | ______ 1.5 | ___ 55 ___ |
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16GB (2x8GB) 1600MHz CL9 RAM comparison
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| _______________ Model ________________ | Works | tRas _ | __ Voltage | Price in $ |
| Kingston HyperX LoVo KHX16LS9P1K2/16 _ | YES _ | _ 27 _ | _ 1.35/1.5 | ___ 129 __ |
| Kingston HyperX KHX16S9P1K2/16 _______ | YES _ | _ 27 _ | ______ 1.5 | ___ 127 __ |
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Annotations:
- The smaller tRas is, the faster RAM is.
- Things marked in bold are good things, things marked in italic are bad things.
- Some RAM does not work in MBP at 1600MHz - only at 1333MHz, because of XMP (eXtreme Memory Profiles).
I have removed the heat spreader column: now, to reduce manufacturing costs,
some companies are using confusing stickers which look like a real heat spreader.
Eventually, I have completed a two-step upgrade:
1) 
Pre-installed Hynix 4GB 1333MHz CL9
----> Corsair Vengeance 8GB 1600MHz CL9 CMSX8GX3M2A1600C9
2) Corsair Vengeance 8GB 1600MHz CL9
-------> Kingston HyperX LoVo 16GB 1600MHz CL9 KHX16L
S9P1K2/16
UPDATED at 15 March 2013
