Replace "left" GPU with a second "Right" GPU for two SSDs is nMP?

[deconstruct60]

Someone should try this.

Can try but highly doubtful it works even if the connectors are exactly the same. Just because there are pins on the connector doesn't mean they are hooked to anything on the main (bottom) logic board. It Apple knew the "B" GPU doesn't have a PCI-e SSD connector what is their motivation for running PCI-e traces from a ribbon cable that has no connector???????

Throw on top that Anandtech said the boards are made by different subcontractors. Even more so drives home the point that they are different.

There isn't another x4 on the C602 chipset. There might be another x4 on the Plex switch but the TB controllers have basically consumed all of that bandwidth. All would be doing to dilute all 4 devices bandwidth if add another one to the already full 'pot'.

 

[deconstruct60]

do you think it's possible we'll see more lanes added with haswell E? (or whatever the next gen equivalent processors are called)

Would have a higher possibilty out of getting more PCI-e lanes out of an updated chipset than directly from the CPU. Probably would not get alot more bandwidth but if new chipset variant nuked or major downsized the SATA portion (not being used at all ) , absorbed USB 3.0 ( frees up x1 ) , and added 3 lanes that are convertible and past the x8 cap currently then would have room for a second PCI-e SSD. Even if chipset freed the x1 discrete USB and add just one could put in an asymmetrical x2 PCI-e SSD ( laptop class part so nothing new ) part.

For example, with just x2 could to a slower 'capacity' SSD with TLC flash that is slower but higher data density.

But likely need a new main logic board design. Pretty much need one anyway for the next generation chipset so wouldn't be a big deal. This design is probably limited.

 

[AidenShaw]

There isn't another x4 on the C602 chipset. There might be another x4 on the Plex switch but the TB controllers have basically consumed all of that bandwidth. All would be doing to dilute all 4 devices bandwidth if add another one to the already full 'pot'.

The bandwidth would only be "diluted" if you ran an artificial "bandwidth virus" load that saturated all the TB channels and the extra SSD simultaneously.

Under actual application usage - you'd probably never be able to detect the oversubscription of the lanes going into the PLX switch.

Probably simpler, though, would be to add another simpler PLX switch on the motherboard (the round board at the bottom) and split the PCIe 2.0 x4 going into the main GPU SSD into two PCIe 2.0 x4 connections, and run the second x4 to the SSD on the second GPU. Since the PCIe SSD is around 1 GB/s, and the x4 link is 2 GB/s, this would be a good compromise. Barefeats might notice a bit of a hit on RAID-0 to the two SSDs - but the more typical case of "OS+apps on one SSD, data/work files on the other" would run just fine.

In spite of what was said at the keynotes and in the ad copy, engineering is always about finding the right compromises. Lots of people would be happy with having a second internal SSD - even if some potential theoretical peak performance would be lost.

And if you can't accept that compromise - simply don't install the second internal SSD. Don't invent lame "justifications" about why Apple wouldn't do something that seems to be one of the most requested features for the next rev of the new Mini Pro.

 

[AndyUnderscoreR]

And if you can't accept that compromise - simply don't install the second internal SSD.

There's no need to compromise at all, there's plenty of bandwidth on the 6 Thunderbolt 2 connections, if you want another SSD, simply plug it in there.

one of the most requested features for the next rev of the new Mini Pro.

No, it's pretty much just you going on about it. Everyone else has wondered why where isn't a second internal SSD, read the explanations posted here, understood that there would be a compromise involved and that there's a better place to put SSDs, and moved on.

 

[AidenShaw]

There's no need to compromise at all, there's plenty of bandwidth on the 6 Thunderbolt 2 connections, if you want another SSD, simply plug it in there.

What would you recommend as a T-Bolt 2 PCIe expansion chassis and a PCIe SSD?