A Call For Measurements: Isolating the Thunderbolt Effect.
 
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A Call For Measurements: Isolating the Thunderbolt Effect.  

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nando4
(@nando4)
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Joined: 4 years ago
 
Posted by: itsage

 I found older BIOS (A02, A04) which had support for Thunderbolt. This Alienware Area 51 R2 is currently running A10 and can't be downgraded through Windows. I'm not familiar with flashing BIOS through DOS.

 

1. Use Rufus to create a FreeDOS USB stick. Set Rufus for MBR boot and use a FAT32 format.

2. Copy https://downloads.dell.com/FOLDER02794314M/1/Alienware_Area_51_R2_A02.exe to the USB stick.

3. Reboot and hold F12 or whatever the key is to manually select boot drive. Point to USB stick.

4. At C:\> DOS prompt type Alienware_Area_51_R2_A02 . If nothing happens or 'bad command or filename' then type 'dir' to identify the filename, then type it.

If have no luck downgrading to A.02 as some vendors prevent rollbaack, then consider fishing through the UEFI variables of your A.10 BIOS to see if can re-enable Thunderbolt. Details of how to do that are here.

eGPU Setup 1.35    •    eGPU Port Bandwidth Reference Table

 
2015 15" Dell Precision 7510 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @32Gbps-M.2 (ADT-Link R43SG) + Win10 1803 // compares M.2 vs TB3 performance inc unoptimized H-CPU BIOS [build link]  


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itsage
(@itsage)
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Joined: 4 years ago
 

Thank you for instructions to flash the BIOS in DOS. I will give this a shot. I'll probably flash it back to A08 first using this approach because it's safer that way. 😀

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VisViva
(@visviva)
Eminent Member
Joined: 4 years ago
 

I want to share a benchmark that I recently came up with, which hopefully can reflex the access time difference between native PCIe and PCH-to-TB-to-PCIe connection. As I mentioned in this post, I used the a software to estimate host to device (H2D) and device to host (D2H) performance. This software is part of the samples in AMD APP SDK3.0 for OpenCL.

After reading its help and playing with it a bit, I ran it against my TB3 external GPU with Akitio Node (RX470) and internal dedicate GPU (Quadro M1000M). I ran it using the smallest size possible, so the time for this transfer may somewhat reflect its latency. Then I compare results from different cases. These cases are combinations of: <eGPU or dGPU>, <active or idle>     

(active/idle means weather the GPU is outputting desktop to a monitor. active is outputting; idle is not)

 

This detailed settings specified are:

  • --testType 3 (clEnqueue[Read,Write], prepinned)
  •  --numBytes 2048 (the min value for this option)
  • --numLoops 2000 (perform this 2000 times)
  • --printLog (show detailed results for each loop, instead of just average)
  • --deviceId <x> (specify which GPU do I want it to run)

In addition to this, I changed one figure in its source so it outputs 10 figures after decimal point (instead of the default value of 3).  

Then I convert the speed in GBPS to time for the 2KiB transmission in microseconds, and I found their medians as well as scatter plots.

 

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eGPU
dGPU

 

 

It appears to me that on my system, the eGPU has longer access time, roughly 10 microseconds longer. (This article cites about 1.5 microsecond of latency per hop with thunderbolt, for reference)

However, this experiment is not well controlled in terms of variables, so everything here is strictly for reference only, and I cannot promise this method's confidence. Apparently there's the difference of NVidia and AMD; also the dGPU has x16 PCIe lanes, while the eGPU has only x4 PCIe lanes for TB controller. Furthermore, I do not know and I cannot guarantee if there are other source of uncertainties in terms of timing.

 

 

 

 

 

 

 

2015 15" Lenovo ThinkPad P50 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @ 32Gbps-TB3 (AKiTiO Node) + Win10 [build link]  

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wimpzilla
(@wimpzilla)
Honorable Member
Joined: 4 years ago
 

Hello,

You can simply confirm that using MSI afterburner and record the frametime while gaming, between both setups.

The lag itself is perceived as variation between the frames, example if 2 frames are at 10ms and the next at 30ms, its still ok, if the 1st are 10ms and the next is 70ms there is a problem and then you feel the lag.

If the 10ms latency added on each frame compare to the pci-e are kept stable, i would not see any issues, but when under stress, the bus will show it's limits so even if the card could achieve 30fps displayed, the frametime output will shows a real 25/28 fps feeling.

If you don't saw any difference into the frametime, then dunno where this latency apply and impact.

2012 13-inch Dell Latitude E6320 + R9 270X@4Gbps-mPCIe (EXP GDC 8.4) + Win10
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2012 15" Lenovo ThinkPad T530 [2nd,4C,Q] + R9 270X @ 4Gbps-mPCIe2 (EXP GDC 8.4) + Win10 [build link]  


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itsage
(@itsage)
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Joined: 4 years ago
 

I tried downgrading the Alienware Area 51 R2's BIOS last night in DOS. It was a no-go.

alienware area 51 r2 BIOS downgrade not allowed

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nando4
(@nando4)
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Joined: 4 years ago
 
Posted by: itsage

 

I tried downgrading the Alienware Area 51 R2's BIOS last night in DOS. It was a no-go.  

Hmm.. worth scouting for a modded BIOS. In parallel, pls save a BIOS dump using Universal BIOS Backup and PM me a link to it (it will have DMI/system tatooing details you might not want public). I'll see if we can get extract a IFR file from it with hidden bios Thunderbolt UEFI variables that can be altered manually with a bootdisk.

eGPU Setup 1.35    •    eGPU Port Bandwidth Reference Table

 
2015 15" Dell Precision 7510 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @32Gbps-M.2 (ADT-Link R43SG) + Win10 1803 // compares M.2 vs TB3 performance inc unoptimized H-CPU BIOS [build link]  


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nando4
(@nando4)
Noble Member Admin
Joined: 4 years ago
 

As an aside, an inkling suggesting TB3-CPU outperforms  TB3-PCH on similar CPU-specced systems. @itsage's proposed testing would quantify this. From here:

 

Posted by: votehart407

 

I am using a Titan X Pascal and the results have been much better [late-2016 15" MBP] VS a Razer Blade and MSI GS 40. I cannot say for certain what is causing the increased performance but it has salvaged the EGPU set up for me. 

 

and here

 

Posted by: votehart407

 

MBP 2016 3dMark Ultra - 6190

GS40 3DMark Ultra - 5989

 10-15 fps improvements in most games.  

eGPU Setup 1.35    •    eGPU Port Bandwidth Reference Table

 
2015 15" Dell Precision 7510 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @32Gbps-M.2 (ADT-Link R43SG) + Win10 1803 // compares M.2 vs TB3 performance inc unoptimized H-CPU BIOS [build link]  


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Yukikaze
(@yukikaze)
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Joined: 4 years ago
 
That is an interesting result, nando. It may also mean that our famous "Thunderbolt performance hit" might actually be a "Route everything through the PCH" performance hit.

Want to output 4K@60Hz out of an old system on the cheap? Read here.
Give your Node Pro a second Thunderbolt3 controller for reliable peripherals by re-using a TB3 dock (~50$).

"Always listen to experts. They'll tell you what can't be done, and why. Then do it."- Robert A. Heinlein, "Time Enough for Love."

 
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ed_co
(@ed_co)
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Joined: 4 years ago
 
Posted by: Yukikaze

 

That is an interesting result, nando. It may also mean that our famous "Thunderbolt performance hit" might actually be a "Route everything through the PCH" performance hit.

   

The courious thing is that there is no other computer out there that has TB3-CPU?? Who find that info, nando4?? Seriously, all the vendors are not taking advantage of the tb3 except apple?? Weird!!

2017 15" MacBook Pro (RP560) [7th,4C,H] + GTX 1080 Ti @ 32Gbps-TB3 (Mantiz Venus) + macOS 10.13 & Win10 [build link]  

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nando4
(@nando4)
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Posted by: ed_co

 

The courious thing is that there is no other computer out there that has TB3-CPU?? Who find that info, nando4?? Seriously, all the vendors are not taking advantage of the tb3 except apple?? Weird!!

   

Apple co-developed Thunderbolt with Intel. PC vendors have and continue to play catchup to Apple's lead.  We now have an anecdotal morsel to drive a quantitative analysis of TB3-CPU vs TB3-PCH performance.  itsage's proposed rig the perfect testbed to do it on.

Here's hoping the CPUs are performance comparable,leaving it to be TB3 PCHvsCPU architecture differences. That's certainly wasn't the case in 2013-2015 15" MBPs whose second tier i7-quad (i7-48xxHQ/i7-49xxHQ) CPUs would run unlocked turbo multipliers with TDP ceilings well above the 47W of say 1st tier PC competitors (i7-47xxQM). 

3dmark11 physics results for both the PC (TB3-PCH) and 15" MBP (TB3-CPU)  would give a clearer picture on the CPU performance variable.

eGPU Setup 1.35    •    eGPU Port Bandwidth Reference Table

 
2015 15" Dell Precision 7510 (Q M1000M) [6th,4C,H] + GTX 1080 Ti @32Gbps-M.2 (ADT-Link R43SG) + Win10 1803 // compares M.2 vs TB3 performance inc unoptimized H-CPU BIOS [build link]  


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