Dropped Frames with Media Express with m.2 SSD

I am attempting to record with blackmagic media express with my GH4 to my PC and cannot get it to work at all. It immediately drops frames. I've done a variety of tests, but the easiest one I know should work is:

1920x1080 resolution 24 frames/sec ->1920x1080 24 frames/sec 8bit YUV

I'm recording to a m.2 SSD. It measures 929.2 mb/s sequential writes, which should be more than enough.

Another factor I've read is the CPU, which my machine is running a 6700K, OC'd to 4.0Ghz, again this shouldn't be a problem.

This is a PCIe card as well, so USB isn't a factor because PCIe bandwidth is massive.

Any ideas?

I'm recording to a m.2 SSD. It measures 929.2 mb/s sequential writes, which should be more than enough.

Did you measure this with the DiskSpeed Utility of BMD?
What card are you recording with.. Specify model.

Did you connect the GH4 with HDMI and if so how long is the cable??

I measured it with CrystalDiskMark which is like an industry standard I/O bench marking utility. Irregardless of that, you can look around and find similar results with a variety of apps on the internet for my m.2 SSD (SMP951). I can't use BMD's disk utility afaik because It's only available for mac and I'm on W10.

The HDMI cable is 15' long, do you think that is a problem? I am recording with a Intensity Pro 4k.

Something that just recently occurred to me was that I have it in a PCIe 3.0 x1 slot, which has a bandwidth of ~950 MB/s. I have a PCIe 3.0 x4 slot available, which is something ludicrous like ~3.5 GB/s. I could attempt to put it in the slot instead.

I appreciate your help.

Hi Scott..

I have Win 10 too.. See Attachment.. (This is my programming PC so just an old Sata Harddrive)

I'm not very used to all the imperial mesurments.. But Google says 15' is 15 feet or roughly 4,5 meters..
While HDMI has cables up to 20 meters.. HDMI was originally specified on very short distances 2 / 3 meters (7' to 10') Beyond that point HDMI is getting degraded..
And HDMI outputs on DSLR's and GoPro's and other handheld cameras are notorious for there weak HDMI drivers.. These ports originally were designed for Photo or video playback when you put your camera direct beside the tv and put a short cable between it..

So my guess is that you could be pushing to the limits of the HDMI with the dropped frames indicating error frames that did not pass the error test..

So take a short HDMI lead and try that to ensure it is not the HDMI length or cable for that matter..

It was an issue with what PCIe lane I installed the card into. I switched it from a PCIe 3.0 x1 lane to a PCIe 3.0 x4 lane.

After reading back your comment about the bus speeds it makes sense now..

1920x1080 resolution in SDI falls under 1,5Gbit/s classification.. (Which should be roughly the same amount of data from HDMI..

So a slot that is just capable of handling 950Mbit/s of data.. will not run smooth with that..
Your choice of putting it in a PCIe 3.0 x4 slot (3,5Gbit/s ) make sense..

This is why people should always write things correctly. PCI-e 3 1x lane is around 985 MBytes/s not mbits/s, so in theory it should be fast enough, but I suspect the card doesn't work properly if not placed in a 4x slot as that is what it's designed to work with.

Also a PCI-e 3 4x slot runs at around 3.9 GBytes/s not 3.5 Gbits/s that's how you get some of the new M.2's running at read speeds of over 3 GBytes/s

This is why people should always write things correctly. PCI-e 3 1x lane is around 985 MBytes/s not mbits/s

Capital "MB" refers to Megabyte. Lowercase "b", "Mb" refers to megabit.

https://en.wikipedia.org/wiki/MB

I used "MB" and "GB" in both of my references when referring to the speed of the PCIe bus. Sorry I was off with the x4 speed.

in your first post you refer to mb/s not MB/s

I'm recording to a m.2 SSD. It measures 929.2 mb/s sequential writes, which should be more than enough.

I have the same issue on Mac running OS X Sierra 10.12.6.
BM Intensity Pro 4K is in a 4x PCI-e slot. Recording from Leica SL via 12"-long HDMI2.0 cable. 4K capture is impossible, as it starts dropping frames within two seconds. 1080p is possible only in ProRes Proxy.
BM Disk Speed Test shows 183.4 MB/s write speed on an SSD installed in a 1x PCI-e slot.

Mac Pro 2008
8-core Intel Xeon 3.16GHz
NVIDIA GeForce GTX 980 Ti
32GB RAM
512GB Samsung EVO SSD

I should clarify... 4K capture is possible in ProRes LT, but nothing with the higher bit rate.
Any takers?