iMac 5K SSD upgrade to PCI-E x4?

[wmy5]

Hi guys,

I am hoping to upgrade the blade SSD in iMac 5K. The SSD used in iMac 5K only has x2 bandwidth, so it is not so fast as the SSD used in nMP and latest rMBP 15". Does anyone know if it is possible? If I get a x4 SSD (blade SSD part for nMP, for example), will it work on my iMac 5K with full speed? Thank you!

 

[yjchua95]

Hi guys,

I am hoping to upgrade the blade SSD in iMac 5K. The SSD used in iMac 5K only has x2 bandwidth, so it is not so fast as the SSD used in nMP and latest rMBP 15". Does anyone know if it is possible? If I get a x4 SSD (blade SSD part for nMP, for example), will it work on my iMac 5K with full speed? Thank you!

It's not possible.

Even if you have a 4 lane SSD inside, it will only operate at two lanes, because the other two lanes are taken up by the extra 2 USB ports and Ethernet port.

On the rMBPs, since it doesn't have the extra 2 USB ports and Ethernet port as found on the iMac, there are an extra two lanes available, leaving a total of 4 lanes for the SSD.

 

[dyn]

The chipset allows for far more ports than the iMac comes with (e.g. the chipset has a max of 16 lanes which can be configured as 1x16, 2x8, etc.). The only reason why you have 2 lanes instead of 4 is product differentiation (iMac vs Mac Pro). I doubt you can get more than that by simply changing the ssd, you probably also need to change the interface, etc. to support more lanes.

 

[jerwin]

For a look at what the Mac Pro does with its PCE-lanes, consult this article.


Sooner or later, you're going to run out of lanes 16 PCIe3 lanes for the video card, 8 PCIe2 lanes for networking, storage, thunderbolt, USB 3.0, aand so on. The iMac has more independent ports than a MacBook Pro, and hence, it doesn't have the extra bandwidth for a 4X SSD.

Blame Intel. Wait for skylake.

 

[dyn]

Do you have some more info on that because it is quite contradictory to what ark.intel.com is reporting about the Core i5 used in the iMac 5k.

We should be careful with comparing it to the Mac Pro though since it uses a different chipset (it uses workstation/server stuff which are a bit different from the normal consumer Core i stuff). Also, the iMac uses a desktop processor whereas the MBP uses a mobile version. There are some minor differences between them.

 

[jerwin]

Hmm. I think there's a way to glean this sort of information in windows (Device Manager) but on a mac, I have no idea. As I don't have bootcamp, can't help you there.

 

[dyn]

You don't need bootcamp for OS X. What tooling did you use on OS X for this?