I don’t know what caused it, but sometime after upgrading to Snow Leopard the performance of my laptop has dropped through the floor. It’s really bad, especially with video – this 2yo mac can’t play a youtube clip without CPU going to 100% and jerking unwatchably.
I’ve been busy so hadn’t had much chance to investigate, but one thing or another led me to suspect memory performance, so today I ran Xbench. As you’ll see, the results speak for themselves.
Memory Test 15.31
System 23.78
Allocate 116.31 427.14 Kalloc/sec
Fill 70.52 3428.64 MB/sec
Copy 9.67 199.83 MB/sec
Stream 11.28
Copy 10.55 217.93 MB/sec
Scale 10.50 216.93 MB/sec
Add 12.76 271.83 MB/sec
Triad 11.61 248.39 MB/sec
That is shockingly bad and a full order of magnitude lower than expected. There’s something seriously wrong here.
The ram is 2×2GB Kingston 667MHz. It was working fine before and continues to work, just 10x slower than it should. Any ideas?
update: i’m going to list some details to make it easier for others with similar issues to find this post by search.
ram details:
BANK 0/DIMM0:
Size: 2 GB
Type: DDR2 SDRAM
Speed: 667 MHz
Status: OK
Manufacturer: 0×7F98000000000000
Part Number: 0×393955353239352D3031312E4130304C4600
Serial Number: 0×160AA70D
BANK 1/DIMM1:
Size: 2 GB
Type: DDR2 SDRAM
Speed: 667 MHz
Status: OK
Manufacturer: 0×7F98000000000000
Part Number: 0×393955353239352D3031312E4130304C4600
Serial Number: 0×160AE80F
system details:
Model Name: MacBook Pro
Model Identifier: MacBookPro2,2
Processor Name: Intel Core 2 Duo
Processor Speed: 2.33 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 4 GB
Bus Speed: 667 MHz
Boot ROM Version: MBP22.00A5.B07
SMC Version (system): 1.12f5
UPDATE: removing one of the 2GB modules returns speed to normal:
Results 126.95
System Info
Xbench Version 1.3
System Version 10.6.1 (10B504)
Physical RAM 2048 MB
Model MacBookPro2,2
Drive Type FUJITSU MHW2120BH
Memory Test 126.95
System 145.21
Allocate 274.47 1.01 Malloc/sec
Fill 111.52 5422.41 MB/sec
Copy 124.24 2566.05 MB/sec
Stream 112.77
Copy 104.49 2158.22 MB/sec
Scale 106.87 2207.96 MB/sec
Add 121.81 2594.72 MB/sec
Triad 119.98 2566.73 MB/sec
This machine is actually only able to address 3GB of memory; previously it ignored the other 1GB without consequence. Seems it might not be without consequence anymore.
Sucks to only have 2GB of memory but the system is now so much more responsive it’s actually a huge win. I’ll continue like this until further information emerges.