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pullman

macrumors 6502a
Original poster
Feb 11, 2008
922
172
¯\_(ツ)_/¯
Hi everyone

I have a late 2008 Macbook aluminium unibody with a Seagate Momentus XT500. I recently placed an OWC 40GB Mercury Extreme (the Sata 2 version) in the optical bay. I could have sworn that System Profiler at that point reported that the Sata bus had a "negotiated link" speed of 1.5 GB/s for the optical bay/Mercury.

Today I swapped places of the drives because I thought the Mercury would likely hit the roof of the real-world speed of the negotiated link.

With the Momentus in the optical bay and the Mercury at the normal hard drive spot, the computer seems to runs hotter. The fan begins to spin audibly even at a light workload, like surfing the internet. Before switching places the fan spun up at high rpm only when I worked in Photoshop etc.

For instance, I just now cold-booted the computer after having had it shut down all night. The CPU temp rises continually. Within a few minutes when I have just edited this message, it's 64 degrees C and rising. The fans run at almost 3800 rpm. Previously they would be at 2000rpm on light load.

System Profiler now says that the optical bay spot has a negotiated link speed of 3GB/s. Like I said, I'm pretty sure it said 1.5GB/s before - could this have changed by switching drives?

And could there be more "strain" on the processor with the drives in the new spots? Seems unlikely to me.

I have reset the SMC with no effect.

Edit: I now switched back so the Momentus is in the optical bay and the Mercury in the normal spot. The negotiated link speed is, in fact, 3GB/s. And, interestingly, the CPU is stable (at light workload) at 46 degrees with the fans inaudibly at 2400rpm.

The mystery, though, is why would the CPU work harder just because the drives are in opposite spots??


Thanks very much in advance for any insight into this
Philip
 
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