Please do not double post (or in your case, triple post.) Instead, use the Edit button to add additional information to your post. I've merged your posts for you.
The $2500 price range you're referring to would be for a small 3-4 GPU exapander chassis, which would be stupid as you could build an entire 4-GPU rig for much cheaper than the price of the expander chassis alone, not even including the price of the GPUs or host system. And actually a good 4-GPU expander chassis (e.g. Cubix XPRM-G3-ELRLE) are around $4600 without the cost of the GPUs, which is more than a Tyan FT77.
Yes, there ARE things that are GPU-specific when dealing with expander chassis, and you SHOULD select a chassis designed specifically for GPUs for three critical reasons: power, cooling, physical dimensions. However, a lot of those expander chassis that are specifically designed for 4+ GPUs cannot physically accommodate desktop cards, as they are typically designed for shorter, low-power, and often passively-cooled Tesla GPUs. Desktop GPUs are longer, are actively cooled, and typically have two top-mounted power connectors vs one rear-mounted power connector found on server GPUs. So desktop GPUs typically cannot physically fit nor can they be powered or adequately cooled in most expander chassis.
I just realized the 16-slot expander you linked to above can only hold 8 GPUs. I don't know if Magma has a true 16-GPU expander chassis, but I do know that the retail price of http://onestopsystems.com/4u-compute-acc...tx-titan-x is $32k with 16x GTX 980, and $45k with 16x Titan X.
I know you're kind of new to this scene, but expander chassis were one of the first things we experimented with ~5 years ago, and we promptly ditched them for the Tyan chassis. An expander is almost always NOT the way to go, the only reason we sell the chassis linked to above is that a host system + 16-GPU chassis + 16 GPUs is cheaper than 2x Brutalis + 1x Magistos + 10Gbit / Infiniband switch. But for less than 9 GPUs, an expander should be out of the question for almost all applications.
Your Plan B chassis almost surely will not work well for GPGPU. Maybe you should check out Chenbro RM41300-FS81 instead.
Plan C is most definitely a no-go.
The $2500 price range you're referring to would be for a small 3-4 GPU exapander chassis, which would be stupid as you could build an entire 4-GPU rig for much cheaper than the price of the expander chassis alone, not even including the price of the GPUs or host system. And actually a good 4-GPU expander chassis (e.g. Cubix XPRM-G3-ELRLE) are around $4600 without the cost of the GPUs, which is more than a Tyan FT77.
Yes, there ARE things that are GPU-specific when dealing with expander chassis, and you SHOULD select a chassis designed specifically for GPUs for three critical reasons: power, cooling, physical dimensions. However, a lot of those expander chassis that are specifically designed for 4+ GPUs cannot physically accommodate desktop cards, as they are typically designed for shorter, low-power, and often passively-cooled Tesla GPUs. Desktop GPUs are longer, are actively cooled, and typically have two top-mounted power connectors vs one rear-mounted power connector found on server GPUs. So desktop GPUs typically cannot physically fit nor can they be powered or adequately cooled in most expander chassis.
I just realized the 16-slot expander you linked to above can only hold 8 GPUs. I don't know if Magma has a true 16-GPU expander chassis, but I do know that the retail price of http://onestopsystems.com/4u-compute-acc...tx-titan-x is $32k with 16x GTX 980, and $45k with 16x Titan X.
I know you're kind of new to this scene, but expander chassis were one of the first things we experimented with ~5 years ago, and we promptly ditched them for the Tyan chassis. An expander is almost always NOT the way to go, the only reason we sell the chassis linked to above is that a host system + 16-GPU chassis + 16 GPUs is cheaper than 2x Brutalis + 1x Magistos + 10Gbit / Infiniband switch. But for less than 9 GPUs, an expander should be out of the question for almost all applications.
Your Plan B chassis almost surely will not work well for GPGPU. Maybe you should check out Chenbro RM41300-FS81 instead.
Plan C is most definitely a no-go.