Oversubscribing PCIe lanes

[russemerson]

I've had a build brewing in my mind for a while, and I've reached, I think, a point that might be described as "my eyes are too big for my stomach" -- that is to say, I think I may be trying to get more out of the components I want to use than they might be capable of handling well... if at all.

 

My basic idea is to have a 5930k on an Asus X99 Sabertooth, with dual GPUs in SLI, booting off an M.2 SSD, SATA SSDs as working space, and then an LSI RAID card to handle the HDDs I'm going to have for bulk storage.

 

And here's where I think I'm running into the problem.  The Sabertooth has 5 PCIe expansion slots, as such:

 

1) PCIe 3.0 x16  referred to as "16_1"

2) PCIe 2.0 x4

3) PCIe 3.0 x16  ... "16_2"

4) PCIe 2.0 x1

5) PCIe 3.0 x16  ... "16_3"

 

Slots 1 & 3 would be for the GPUs.  It's the remainder where I think I have a problem.

 

[bTW, I'm working from the PDF manual at Asus' site.]

 

First, the manual states (page 1-37 if you're following along) that the M.2 socket shares bandwidth with slot 16_3.  Then later (p. 3-47) it gets a bit more explicit, and says that 16_3 is disabled when an M.2 drive is installed.  That's not sharing... that's taking your ball and going home.

 

Next, the RAID controller... [specs here] ... which seems to require PCIe 2.0 x8.  So, if I want to run the RAID card, I'm thinking it would have to go into slot 16_3... which, as noted above, is disabled when M.2 is in play.

 

An alternative might be to use a PCIe M.2 adapter card, which would then allow slot 16_3 to be used for the RAID card.  However, the adapters I've seen so far seem to want PCIe 3.0 x4.

 

I'm screwed here, aren't I?

 

So, I think I could go a couple different paths...

 

1) drop the RAID card altogether and use the mobo SATA ports + software RAID, or

 

2) ditch the SLI plans, cowboy up, and get a GTX980Ti.

 

Anyone have any other alternatives I might consider?

[Enderman]

a PCIe x4 card works in anything that is x4 or above...so it works in x16...

[Sam Z Man]

Bro you could do all that on the 24 lanes of a 5820K save the money.

[russemerson]

a PCIe x4 card works in anything that is x4 or above...so it works in x16...

 

Right, but if the RAID card is in play in the third x16 slot, with 2 SLIed GPUs in the other x16 slots, that only leaves a 2.0 x4 slot and a 2.0 x1 slot for an M.2 adapter.

[Devon_Pearce]

get a rampage 5 extreme

[Enderman]

Right, but if the RAID card is in play in the third x16 slot, with 2 SLIed GPUs in the other x16 slots, that only leaves a 2.0 x4 slot and a 2.0 x1 slot for an M.2 adapter.

your motherboard does not have enough PCIe lanes for two GPUs, a PCIe M.2 SSD, and a raid card

[russemerson]

your motherboard does not have enough PCIe lanes for two GPUs, a PCIe M.2 SSD, and a raid card

 

Yeah... I'm thinking software RAID is going to meet my needs on that front, and should eliminate the contention.  Thanks.

[Sam Z Man]

get a rampage 5 extreme

 

No

[Devon_Pearce]

No

awe why not I have one and its amazing

[Sam Z Man]

awe why not I have one and its amazing

 

Because its a absolute waste of money

[Devon_Pearce]

hahaha yeah it was but I have to say I quite like it in my computer. Oh well I tried. I own a Z77 Sabertooth, and I had looked at the X99 Sabertooth, but I wanted to ensure maximum expandability in my system, not how much it resembled a brick shit house.

[Sam Z Man]

hahaha yeah it was but I have to say I quite like it in my computer. Oh well I tried. I own a Z77 Sabertooth, and I had looked at the X99 Sabertooth, but I wanted to ensure maximum expandability in my system, not how much it resembled a brick shit house.

 

If you want expandability with anything get a MSI x99s sli plus for 200$.

 

M.2 check

4 way sli check

4 way crossfire check

 

What else is there.

[Devon_Pearce]

6 sata 3 on the intel controller

4 sata 3 for disk drives and such

sata express 

and all the OC crap i could ever want.... And i dont mind paying 550 bucks after tax for a motherboard.