AMD AM3+ Motherboards with PCIe 3.0?

twright70

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Apparently there's only one in existence, the Sabertooth 990FX Gen3 R2.0 which came out back in 2013:
SABERTOOTH 990FX/GEN3 R2.0 - Overview

I recently purchased a Samsung 950 PRO NVMe 512GB M.2 drive, along with a Lycom DT-120 adapter to use in my older Asus M5A97 R2.0 motherboard, which uses PCIe 2.0. I verified from a fellow user that this will work; however, I will not be getting the full 20Gb/s data transfer rate.

The Gigabyte GA-990X-Gaming SLI (rev. 1.0) "claims" that it can do up to 20Gb/s (they put in the ad a * which indicates this is 'theoretical') on a board that only has PCIe 2.0:
GIGABYTE - Motherboard - Socket AM3+ - GA-990X-Gaming SLI (rev. 1.0)

First, I think the Gigabyte page above will mislead people to believe that getting the full 20Gb/s on a PCIe Gen2 x4 M.2 will be possible on this board. I could be wrong. Can anyone verify this?

I've seen some AMD FM2+ motherboards that have PCIe 3.0, but my understanding is that the AM3+ processors are far superior. Can anyone verify this for me, as well?

The biggest question I have is, are there any other AM3+ motherboards out there that have PCIe 3.0? Or are there going to be any coming out in the near future? If not, this may have convinced me to go with an Intel board/processor for my next upgrade.
 

Tsumi

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No point, the HyperTransport connection is the bottleneck.
 

Track Drew

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PCIe 2.0 x1 = 5 GT/s (500 MB/s)
PCIe 2.0 x4 = 20 GT/s (2000 MB/s)

That's the facts. The Gigabyte board states it's "PCIe Gen2 x4 M.2". Now they say it's 20 Gb/s. 2000 MB/s x 8 bits/byte = 16000 Mb/s ~16Gb/s (a little less)

My guess is since the M.2 connector includes both PCIe x4 and SATA:
SATA3 = 600 MB/s

600 MB/s (SATA) + 2000 MB/s (PCIe) = 2600 MB/s ~20800 Mb/s

20800 Mb/s / 1024 = 20.3125 Gb/s

So the slot can do ~20Gb/s across all the interfaces... Marketing...

As far as HyperTransport goes (numbers from here: Everything You Need to Know About the HyperTransport Bus - Page 4 of 5 - Hardware Secrets)
An AM3+ FX chip will run the HyperTransport link at 2,600 MHz = 5,200 MT/s = 10,400 MB/s = 83,200 Mb/s = 81.25 Gb/s
An AM3 (Phenom II) chip will run the HyperTransport link at 2,000 MHz = 4,000 MT/s = 8,000 MB/s = 64000 Mb/s = 62.5 Gb/s

On paper, I don't think HyperTransport is the bottleneck, but I could be wrong. Would need to find some benchmarks - I'm sure there's a slight performance hit.

Can you post benchmark results of your drive? Advertised sequential read/write of that drive is around 2,500MB/s and 1,500MB/s respectively. I'm guessing you're maxing out at PCIe 2.0 x4, so around 2,000 MB/s.
 

twright70

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I was able to setup the Samsung 950 as a boot device on my old board, no problem. The bios; however, takes a while before it recognizes the SSD (it hangs at the RAID controller), but man, once it gets past the post, Windows comes up in about 15 seconds or less. After installing the Samsung Magician software and the Samsung NVMe Controller I'm getting the following results.

Samsung Magician

Samsung 950 PRO M.2
Capture1.png


2x 2TB 7200 RPM Drives on RAID0
Capture2.png


CrystalDiskMark

Samsung 950 PRO M.2
Capture3.png


2x 2TB 7200 RPM Drives on RAID0
Capture4.png


ATTO Disk Benchmark

Samsung 950 PRO M.2
Capture5.png


2x 2TB 7200 RPM Drives on RAID0
Capture6.png


Despite the fact that I'm not getting the full 20Gb/s, I'm still a pretty happy camper.

Thanks for the responses. I'm disappointed that AMD board manufacturers aren't including PCIe 3.0 on their AM3+ boards. I think I'll probably be joining the dark-side (Intel) for my next upgrade unless by weird coincidence they come out with one here in the near future.
 
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Track Drew

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Those pictures are tiny.

I'm disappointed that AMD board manufacturers aren't including PCIe 3.0 on their AM3+ boards.

Not much to do with board manufacturers, the AMD 900 series chipset just doesn't support PCIe 3.0. Obviously, at least one has added in some type of bridge chip to supply GPUs with PCIe 3, but this isn't a cheap or native solution. The benefits it has are also questionable - would need to see a block diagram of the motherboard to really know what's going on. The platform has been mostly end of life for some time now, so there's been little development put into it.

Your average PC user isn't even saturating PCIe 2.0 yet, but you're definitely in the 1% with a SSD like that.
 

twright70

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Those pictures are tiny.

Awww, man...I thought it would allow you to enlarge them. I'll update the post with images you can actually see.

Yeah, I'm not an expert when it comes to the technology behind the motherboards. I'm no computer scientist or engineer. I saw another SSD from Kingston - the HyperX Predator Gen2 x4 SSD:
Predator PCIe Solid State Drive – 240GB, 480GB | HyperX

The Samsung 950 Pro is only like $16 more, plus $25 for the HHHL adapter. So, I figured I can spare another $40-50 to get the good stuff. Although, I'm pretty sure they're going to have something better before long - might should've waited until I get a board that can handle PCIe 3.0 before splurging. Only reason I got it is because the wife was complaining that her computer was too slow (she was using 5400 RPM drives in her computer). So I gave her my old Samsung 850 EVO SATA III drive. Win-win. :)
 
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Tsumi

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The connection to the southbridge is basically a PCI-E 2.0 4x connection. That will bottleneck any connection you make on the southbridge side of things (slots that are not designed for GPUs).

As for a PCI-E 3.0 based chipset, there's no point. First being that the HT connection is a bottleneck (for x16 PCI-E 3.0, aka GPU) purposes, and that it is a dead end socket. The latest CPUs for AM3+ were released 4 years ago (I don't count the refreshes of the same architecture as a new CPU), and there won't be a new one for AM3+. It's all about Zen, which will be on a new socket.

As far as FM2+ processors vs AM3+... AM3+ only has the advantage due to the number of cores. FM2+ has newer architectures (latest is Excavator), which while not major, still has IPC improvements over the latest AM3+ architecture (Vishera).
 

twright70

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The connection to the southbridge is basically a PCI-E 2.0 4x connection. That will bottleneck any connection you make on the southbridge side of things (slots that are not designed for GPUs).

As for a PCI-E 3.0 based chipset, there's no point. First being that the HT connection is a bottleneck (for x16 PCI-E 3.0, aka GPU) purposes, and that it is a dead end socket. The latest CPUs for AM3+ were released 4 years ago (I don't count the refreshes of the same architecture as a new CPU), and there won't be a new one for AM3+. It's all about Zen, which will be on a new socket.

As far as FM2+ processors vs AM3+... AM3+ only has the advantage due to the number of cores. FM2+ has newer architectures (latest is Excavator), which while not major, still has IPC improvements over the latest AM3+ architecture (Vishera).

Thanks for the insight!

So, what I got out of this is M.2 SSD's running on PCIe 3.0 slots is not ideal. However, what about motherboards with NVMe M.2 sockets on the board itself? They still say PCIe 3.0 x4. Will there still be a bottleneck issue on those boards, as well? Is this specifically true for just AMD boards, or will Intel boards experience the same bottleneck?

I'm actually very pleased with the performance, so far...I haven't experienced any issues...yet. But then again, maybe I'm not sure what I'm looking for.
 

Tsumi

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It depends on how the motherboard makes the connections. It also depends on the technology in play.

With Intel's DMI 3.0 that is on Z170 chipsets, the connection between the chipset and the CPU is faster than AMD's. The Z170 chipset can do approximately 40 GB/s from chipset (Intel processors do not have a northbridge, so the southbridge is the only chip) to CPU. Compare that to AMD's HyperTransport 3.0 (which is the connection between CPU and northbridge, which provides the PCI-E connections for the GPUs), which does about 10 GB/s in the 9xx chipset, and you see why it is a huge bottleneck. For reference, the UMI interface used for AMD FM2 chipsets (FM2 does not have a northbridge either) is basically a PCI-E 2.0 x4 interface, which does about 2 GB/s.

The technology gap between Intel and AMD is not just in CPU performance, it is almost quite literally in everything else as well.
 

twright70

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Thanks for your help! I think y'all just convinced me to go Intel for my next upgrade. :p I may wait to see what happens when the new Zen processor comes out.
 
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Those pictures are tiny.

The 900 sires is a re badge from the 800 sires chip set dating all the way back to the 890GX and FX days

800 sires
https://en.wikipedia.org/wiki/AMD_800_chipset_series

https://en.wikipedia.org/wiki/AMD_900_chipset_series

I have been knowledgeable about AMD since 1996 i was forced to move to intel because the lack of features and outdated chip sets that AMD has.


Not much to do with board manufacturers, the AMD 900 series chipset just doesn't support PCIe 3.0. Obviously, at least one has added in some type of bridge chip to supply GPUs with PCIe 3, but this isn't a cheap or native solution. The benefits it has are also questionable - would need to see a block diagram of the motherboard to really know what's going on. The platform has been mostly end of life for some time now, so there's been little development put into it.

Your average PC user isn't even saturating PCIe 2.0 yet, but you're definitely in the 1% with a SSD like that.
 

kirbyrj

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Your Samsung rates are similar to mine with the MyDigitalSSD BPX drive. Seems like that's the limit for AM3+.
 
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twright70, did you need to change any settings in the BIOS of the M5A97 in order to get that drive to work? I have the same board and the Samsung 960 EVO 500GB M.2 drive, along with a Lycom DT-120 adapter.

It seemed to be loading windows 10 with no problem, but when it tried to reboot it tells me to Insert Boot Media
 
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