PCI-E RTL8126 - 5Gbit/s Windows 7 - 32 / 64 bit driver - exists?

[ruthan]

Hi,
i slowly trying to get away from 1 Gbit networking, becuase it was too long from 1 Gbit age and 100-120 MB/s transfer speed is slower than speed of modern SSDs, even moder HDD can do 200-250 MB/s 6 /8 TB or bigger probably even more.

 So i bough some cheap 5 Gbit card with Realtek chip - RTL8126 , i expected problems - no existing drivers with Window XP, but i was suprised that i cant find even Windows 7 driver, especially 32 bit. 

  I downloded drivers, from realtek site https://www.realtek.com/Download/List?cate_id=584 thre are listed XP / Win 7 / Win 10 / Win 11 drivers, but when you actually check inf files for Windows 7 there is max 2.5 Gbit chip listed -  RTL8125, i have tried to install to install 2.5 Gbit driver in WIndows 7 but driver its installed without exclamation mark in Device manager, but NIC is unable to negotiate network connection.

   So question are there such official or unofficial drivers?
  Yes i how there cards with Intel Chip (520/540) - even 10 Gbit, but they need long PCI-E slots.. I did not tried to place them to short slot, maybe they will work there at slower speed.. they are PCI-E v2 - if im not wrong.. so 512 MB/s max, yeah that is still better than 120 MB/s.

 

Edited October 13, 2025 by ruthan

[canonkong]

Only have mod drivers, and it needs kmdf1.15, so need to port the wdf0100.sys driver from win10 1507, than mod the realtek win10 driver.

Edited October 16, 2025 by canonkong

[ruthan]

Hi, i a bit confused what is exactly kmdf 1.15, are they ready to work with Windows 7, or its work in the progress?

[K4sum1]

I got this card and try properly modding the 7 driver, but it didn't work.

On 10/16/2025 at 9:48 AM, canonkong said:

Only have mod drivers

The way your phrase this, makes it sound like mod drivers exist. Do they? If not, how does one port wdf0100 from win10?

[user57]

these drivers (like wdf0100.sys) represent something
to make an example you can have a hdd/ssd on like win98 and use that setup of OS

that is because the communication like input/output/control are often the same
often the norms are also the same

there a modded drivers and kernel extenders (the ones based on kernel-mode not the ones for usermode dlls)
a such modded driver would be the PAE extension (there are some releases not all mod the driver itself or not very hard) 

so if somebody has written a driver only for windows 10 it might only run on windows 10 
not always because functions are missing
that c-runtime,std problem are also such things
i wrote a code 100 % without a vista (or higher) function, then i saw that still vista functions where added up
so i disassembled the code - what really made my code non functional and:

https://msfn.org/board/topic/182888-how-vs-makes-working-code-still-incompatible/

thus the compiler connects you with functions you not even use, it auto generate them 

so this are some problems you probaly run in

 

a must say is that i dont know the driver´s functions named here 

but if you want to port an entire driver is like big stuff, there often 300 functions
so can you really handle that ? (and then if you dont have that open source not C it would be like pure assembly - what means even more work)
so the other approach would be to look what a open source driver is doing
(sure there are functions probaly even on linux - but this time you have insight (either its called function or what the related driver to with the device (in this case the RTL8126 chip))
and could write your own implementation
and still its a lot to read out - even that way around

a different approach can also be a kernel extender for kernel-mode there is this project:
https://msfn.org/board/topic/183464-compiling-acpi-v20-driver-for-windows-xp-sp3-and-windows-2003-sp2-x32x64/

 

 

also to mention in this case the company realtek is a entire company - we are just a few people
it is not always skill being asked - often teamwork and often size
this is asking much 
and there many things thing on the table ... not only that realtek question

from a different direction, why it always has to be the absolut maximum speed ? i buyed slower drives 
i even didnt change my BNC cable in the past just to have a few faster transfers
i not even use a 50mbit internet connection - why ? just for 4k/60fps ? maybe 8k/60fps ? is the website even offering that speed ?
or is it something else that is being searched ?

win10 and 11 are slow for a reason, they have like very big engines for a next engine, scripts over scripts
but that things shrink if you have a very powerful cpu - or sometimes a hardware solution for a codec (ok sure we have AVX or something) but still ... 

 

[K4sum1]

On 4/1/2026 at 2:08 PM, user57 said:

these drivers (like wdf0100.sys) represent something

So, I meant that a bit more as a hypothetical. I know I will not be able to backport wdf0100.sys on my own, and with my (limited) driver knowledge, I'm not so sure it could be backported. So I'm kinda asking them to back up the claim with a method to try.

However now that I got around to looking, I noticed with Dependency Walker, the driver does not import from wdf0100.sys at all. Instead it imports from ntoskrnl.exe, hal.dll, ndis.sys, wpprecorder.sys, and wdfldr.sys. On Windows 7, ntoskrnl.exe is missing MmMapIoSpaceEx, ndis.sys is missing NdisMIdleNotificationComplete, NdisMIdleNotificationConfirm, and NdisMResetMiniport, and wpprecorder.sys is entirely missing.

George King's NTOSKRNL_Emu has a MmMapIoSpaceEx implementation, wpprecorder.sys looks like it could be stubbed, however not sure what to do about ndis.sys.

However I noticed on Windows 8.1, it's just MmMapIoSpaceEx, and imp_WppRecorderReplay missing. I almost want to use the NTOSKRNL_Emu, and swap imp_WppRecorderReplay with a random function and see what happens. Will try that at some point.

On 4/1/2026 at 2:08 PM, user57 said:

from a different direction, why it always has to be the absolut maximum speed ? i buyed slower drives 
i even didnt change my BNC cable in the past just to have a few faster transfers
i not even use a 50mbit internet connection - why ? just for 4k/60fps ? maybe 8k/60fps ? is the website even offering that speed ?
or is it something else that is being searched ?

Network connected storage. Even just an array of 10+ year old hard drives can saturate a 1G and even 2.5G link.

Also not even that, modern boards are shipping with the RTL8126, so it literally becomes the ability to use the built in Ethernet.

[K4sum1]

1 hour ago, K4sum1 said:

However I noticed on Windows 8.1, it's just MmMapIoSpaceEx, and imp_WppRecorderReplay missing. I almost want to use the NTOSKRNL_Emu, and swap imp_WppRecorderReplay with a random function and see what happens. Will try that at some point.

Tried it. and got a code 37.

[user57]

those 1G and 2,5G link devices useally dont reach that speeds from the internet
lets say you have 50mbit and and 1g and 2,5g wlan router it only reach 50mbit
then even if you have 50mbit the website often give you that speed either - depents but also happens

you guesses right you can look what that driver is missing
so you right too, yes you can add these functions to ntoskrnl 
but then you still have wpprecorder.sys missing
and here i see a fault - very likely that wpprecorder.sys use even other system driver files and functions
so you run from one into a other problem , you would have to look with that depencency walker also that wpprecorder.sys
and there you probaly find high bonds with other win10+ drivers

the other solution (to reach out that entire wdf0100.sys driver and its functions)
you can write a other solution to solve the things (whatever this precise file is doing - but it always represents something)

for linux it would be the same - but unlikely there you have insight in all 3 of the things 
you would have the old code of ntosknrl you would have the ntoskrnl with that missing functions
you would have the wdf0100.sys code and you would also have the wpprecorder.sys code
and even if it use a next sys file you got that code too
so it would be about understanding what it is doing
even if that not is possible it would be possible to combine all in 1 sys file 
in that case you would take all the functions and put them into wdf0100.sys or something 
they dont have to be split apart

also to notice often some structures from drivers to driver have differences, that PAE patch had that kind of problem
in that case dependency walker dont show this part - useally that tool is enough but

to backport the entire driver from a assembly source is many many more work then just having the c code - a must say

in same cased like dwrite.dll the exported function is a interface in this case 
you might see one import - but its a lot more of functions - its something to consider maybe maybe not

dietmar´s approach was i think that he rewrite a own interpretation how to talk/control to that device
that should be possible - however also big work - in this case having a working driver code would be worth a lot

a must mention is that later windows always gone into a engine solution

a engine solution also includes often severial files to solve the things up - that litterally ask for severial files

i dont know the norms to control that either - that would be something to lern

 

however the discussion recently about similar things always go like "talk" "we install a driver good to go"

we might actually dont have this we are not in a RTL(X) support forum and asking for some drivers for a certain OS - it wont be as simple as that

 

that acpi discussion also again rather wants to talk about a windows 2000 support, what is kinda bad for the XP community as i wrote about that kinda often
 

[ruthan]

My one reach 160 MB/s, but there some people which claims to get full 240 MB/s, but there are some guide how to get more but tuning lots of Device manage advanced settable parameters,
i have tried, so far i failed but its hard to point it to USB ethernet device or to router.
   Check this post:

 At least one my machine i started after while problem with USB devices disconnecting from manage and reconnecting, with both 2.5 + 5 Gbit adapters, but it could be problem of used controller.. Because USB controller firmware update is nightware especially with cheaper ones, which are using different chips, i bricket some just by trying yeah you can return them to original state by using CHip programmers.. but for upgrade you need some magic chip details values and there are sometimes hard to get, you have low level knowledge of this stuff.. or have to find somebody who can find them for you in by understanding of datasheets.

So manufactures problem trying to save on some additional chips.

Edited April 3 by ruthan

[K4sum1]

16 hours ago, user57 said:

those 1G and 2,5G link devices useally dont reach that speeds from the internet
lets say you have 50mbit and and 1g and 2,5g wlan router it only reach 50mbit
then even if you have 50mbit the website often give you that speed either - depents but also happens

The point isn't to connect to the outside world at high speeds, it's to communicate inside my network at those high speeds. Across computers on the same local network.

Also outside of that, I mean modern boards are using this chip now. If I'm to upgrade to AM5, my top two boards use the RTL8126. So I'll want this to work.

16 hours ago, user57 said:

dietmar´s approach was i think that he rewrite a own interpretation how to talk/control to that device
that should be possible - however also big work - in this case having a working driver code would be worth a lot

I think since Dietmar got RTL8125 working, I might be able to get RTL8126 working, but haven't tried looking at the driver. I'd need to figure out why x86 driver crashes my Ryzen system with a RTL8125 , and/or compile x64 driver to test with XP x64 to develop with.

16 hours ago, user57 said:

that acpi discussion also again rather wants to talk about a windows 2000 support, what is kinda bad for the XP community as i wrote about that kinda often

How is that kinda bad?

Edited April 4 by K4sum1

[user57]

hmm its going in a different direction its getting very off-topic
the calculation for speed is simple /8 /1024 (kb) / 1024 / (mb)
so to answer this one
1 Gigabit would represent 125 Megabyte/second
2,5 GBit would be 312,5 MByte/second 
ruhan only reached 160 MB/s what is far from 312,5 MB/s

i dont know if ruhans hard or software can combine these or not - that is possible (in the past called multilink for example with ISDN)
if it suppose to do that 312,5 * 2 = 625 mb/s

if its 2,5 + 2,5 + 5 = 1250 mb/s

to mention now is that a dsl or internet speed test are fast servers they suppose to reach that value
but often you need far less, special from websites
even for a video look the file sizes taken from the ytdl discussion:
https://msfn.org/board/topic/184368-who-here-has-a-youtube-dl-compile-for-winxp/page/41/
the files are not big either
(with K in the ending kilobit is meant)
232 mp4   1280x720    24    | ~185.82MiB  1425k <- for that one 0,173 MB/s
399 mp4   1920x1080   24    |  161.10MiB  1235k <- for that one 0,15 MB/s
625 mp4   3840x2160   24    | ~  2.39GiB 18784k <- for that one 2,29 MB/s 
401 mp4   3840x2160   24    |  948.58MiB  7273k <- for that one 0,887 MB/S

a 50 mbit connection has 6,25 megabyte/s

(also to say that even if you have 10 GB internet youtube at maximum gave you 2,29 mb/s of 1250mb/s)

for games that question is even far smallers, games only progress like positions, lean, headposition, button flags
so that transfer is very small even with a 33,6 modem you useally can play

then also webbrowsing - these websites are useally small things - why a such server would offer or need a such speed ?

 

 

that 2000 question is doing us XP users no good
1 reason is that XP is just a good successor to win2k for example it can use the systenter command and run a lot faster 
while XP lose like zero compatibility and give more functions 
if you know what devide and conquer is i could write a long text
but short to give us trouble is giving us splits aka trouble
and the todo list is like very very very high - it is often said - ya no problem now we make a vista thing in between (where is the room for that?)
yet they want to talk about windows 2000 make it - what the xp movement rather cant
if the win2k users want that ok no problem - but jumping around certainly do XP no good - we can give you codes from us
but then youself is ask

that win2k offers more options - no not backwards not forwards, even a i486 cpu is working with some mod´s of XP (i think a guy called dietmar made that one - he might missed TLS 1,3 (there is a driver with cpuid there)) but useally his solution works for a i486 cpu
https://en.wikipedia.org/wiki/I486

that is going like way back - so what exactly win2k offers ?

its s similar question with vista vs 7 - 7 has less bugs more speed and barly compatiblity losses 

(as you might remember i got pretty angry when you put me vs a vista question, i wasted a lot of time for nothing there - it already was a lot to do

and no its not like we do this just in a second or so - its a lot of things (and then vista sideby ? no - and win2k ? no))

 

well the new hardware thing is definatly something - that RTL chips that control the cat8 cable in the past where not made onboard

they useally where made with a card called someting like "Gigabit Ethernet Network Card" 

you would have the choice to buy a card instead - just saying - the solution to have a driver is a better solution but i very agree on this one

[ruthan]

WIndows XP are limited to 1.4Gb/s (170 MB/s) even with Intel 10Gbit card, no USB involved, its some design feature in system which is blocking more, someone would have to fix it, to enable more.. 

I searched, i could be because:
- no Receive Side Scaling (RSS) - so all is done on single core
- Lack of Hardware Offloading -  network card hardware is not use and all is calculating by CPU, i hope its not case of Intel drivers, but im not sure if XP supports all needed stuff to do it

But i also found that 1.4 Gbit could be just some XP connection speed reporting problem.. 

[user57]

hmmm if you want to fix that
collect all the chains of code that control that transfer, then logic should tell what exactly the problem is
a microsoft developer might know where already
we dont know and/or how they written the code to solve this

still only going with the transfer rate 170 mb/s would be 77, 4k video´s at once
it would rather open the 4 GB ram question again, to extend that not over multiple app´s/executables/running programs
but over the use of the segment registers and changing the paging mode (and changing the related codes)

 

im busy with others things, the chromium or supermium author probaly with his stuff

i think we really would need more people, studying the related codes would need time

[canonkong]

On 4/1/2026 at 3:09 AM, K4sum1 said:

I got this card and try properly modding the 7 driver, but it didn't work.

The way your phrase this, makes it sound like mod drivers exist. Do they? If not, how does one port wdf0100 from win10?

Realtek win10 drivers need KMDF 1.15.
KMDF1.15~1.19 port to win7 is not hard. We successfully made KMDF 1.15~KMDF 1.33 work on win7.
win10 usb driver also can work on win7.
WiFI6/6E and some WiFi7 also can work now, need to extand win7 ndis.sys to support wdi, need to port wdiwifi.sys from win10.
Here is the driver:https://forums.mydigitallife.net/threads/3-posts-for-extending-win7-on-new-hardwares.89805/

Edited April 6 by canonkong

[canonkong]

On 4/1/2026 at 3:09 AM, K4sum1 said:

I got this card and try properly modding the 7 driver, but it didn't work.

The way your phrase this, makes it sound like mod drivers exist. Do they? If not, how does one port wdf0100 from win10?

Use IDA Pro to edit the KMDF 1,15~1.19 file:
DriverEntry: 48 to C3

Use "mov eax, 0C0000001h" to relace the unsupport IAT, jut need to fix  relace IoGetActivityIdIrp and PoFxRegisterDevice
For Extimer, find ExAllocateTimer, than make it don out use Extimer IAT, like jz  $LN10 to jmp   $LN10, it will use FxTimer::_FxTimerDpcThunk, not use FxTimer::_FxTimerExtCallbackThunk.
Than all unsupport IATs, just use a short support IAT to replace them use PETools, also can nop them because they will not be used. But for KeInitializeSpinLock only can use RtlRunOnceInitialize repalce it.

 

Edited April 6 by canonkong