Okay, I'm about to feel brilliant -- or like an idiot.
We see that an SM951 attached to the Lycom DT-120 adapter and inserted into a x16 PCIe slot in a cMP fails to properly negotiate the x4 connection and operates at only half link speed = 2.5 GT/s. Move the combo to a suitable x4 slot and we see full link speed = 5.0 GT/s.
I'm wondering if the x16 slot can undergo a simple tweak to trick the SM951 into thinking the Lycom adapter is seated in a native x4 slot?
I began wondering about this after stumbling across the Amfeltec PCI Express Filler.
It is a mechanical device simply to stabilize longer cards. Obviously it won't do the trick.
But it made me wonder if maybe there exists a "filler" or "isolator" that can dupe a x16 slot into behaving electrically like a native x4 slot? Some way that a line of goldfingers can isolate the first 4 lanes from the other 12?
I know technically that shouldn't be necessary because x4 cards are supposed to work just fine in x8 and x16 slots, but for the sake of workaround it would be interesting especially if it were inexpensive and reliable.
If such a thing even exists, I imagine it's marketed for test/debug. I started looking but haven't found anything.
Thought I'd toss up the idea and see if anyone can help run with it (or put it out of my misery!)
We see that an SM951 attached to the Lycom DT-120 adapter and inserted into a x16 PCIe slot in a cMP fails to properly negotiate the x4 connection and operates at only half link speed = 2.5 GT/s. Move the combo to a suitable x4 slot and we see full link speed = 5.0 GT/s.
I'm wondering if the x16 slot can undergo a simple tweak to trick the SM951 into thinking the Lycom adapter is seated in a native x4 slot?
I began wondering about this after stumbling across the Amfeltec PCI Express Filler.
It is a mechanical device simply to stabilize longer cards. Obviously it won't do the trick.
But it made me wonder if maybe there exists a "filler" or "isolator" that can dupe a x16 slot into behaving electrically like a native x4 slot? Some way that a line of goldfingers can isolate the first 4 lanes from the other 12?
I know technically that shouldn't be necessary because x4 cards are supposed to work just fine in x8 and x16 slots, but for the sake of workaround it would be interesting especially if it were inexpensive and reliable.
If such a thing even exists, I imagine it's marketed for test/debug. I started looking but haven't found anything.
Thought I'd toss up the idea and see if anyone can help run with it (or put it out of my misery!)