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Windows 7 Systems and Gigabit Networks + 802.11n Transfer Problems

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February 20, 2010 5:24:22 PM

Hi All,

I have just upgraded my home network to a gigabit network (Wired) and an 802.11n (Wireless) throughout the house!

Some of the gear I am using include:

Windows 7 - 64 bit Desktop Computer with Velociraptor 10k HDDs in RAID 0, ASUS P5B Deluxe MB, Intel Core Duo 6800 Extreme Processor, Gigabit Ethernet Adaptors.

Windows 7 - 64 Bit Dell XPS Studio 16 Laptop with Intel 5300 802.11n Wireless network adaptor.

Netgear 10/100/1000 Switch

Netgear Stora, 1TB NAS device, 1000Mbps NIC

PS3, TVIX Dvico 6500A etc etc...

The Issue I am having is with file transfers. It doesn't matter whether I am transfering a lot of small files or 1 large single file! File Transfer Rates seem to be extremely low!

I have read other forums with people using WIN 7 systems with very low transfer rates over the network also, and there doesn't seem to be a lot of answers!?

Firstly, when I transfer files from my DELL XPS to either the STORA NAS or my Desktop Win7, I never get anything more than approx 5MB/s. This is using the 802.11n Wi-Fi network.

When I transfer from my Main Desktop WIN7 computer to the Stora NAS via 1000mbps Ethernet LAN, the files degrade to never going above 5MB/s.

I have tried many different combinations and nothing seems to make a difference until I read something in a forum at Microsoft this evening.

It suggested that I Disable "Superfetch" in the systems services, and turn off "Remote Differential Compression" in Windows Features, and then restart my computer. I tried this and excellent!!! I can now get 21.5MB/s transfer rates from my WIN7 Desktop to Stora NAS device over the 1000mbps LAN.

This gave me a performance increase of over 400% why has WIN 7 got these enabled by default if it causes such problems????

I tried these fixes on the DELL XPS, but the Laptop still can't get above 5MB/s transfer rate, even though the Wireless network is connected at over 200mbps???

Looking at the Network Performance Monitor for my 1000mbps NIC on my main WIN7 Desktop system, the NIC never delivers more than 20% throughput which seems so inefficient!?!?

Although 21.5MB/s is not impossible to live with, I feel I should be getting in the region of about 100MB/s for a gigabit LAN setup.

I was very surprised that those WIN7 tweaks brought me from 5 MB/s to 21.5 MB/s in a couple of minutes and a reboot!!!

Is there any other things people can think of to get my transfer rates right up where they should be??

Much appreciate any help you can give...

Regards,
IanJF
February 20, 2010 5:53:17 PM

Whenever possible, I recommend making measurements using NetCPS and/or Iperf. That will produce the most accurate numbers without incurring any bias due to IO, hard drive latency, etc. Obviously this isn’t possible (e.g., NAS). But between desktop/laptops it certainly is. If you then see a dramatic degradation wrt specific applications, at least you know it’s not the network (i.e., an inefficient or misconfigured network adapter).

Also (and this one isn’t always obvious to ppl), when using wireless in infrastructure mode, realize that access to the wireless AP is serialized. So let’s imagine you have two desktops, each connected by wireless to your wireless router. And let’s assume it’s an N router and will support a real world speed of 100mbps (just to pick something). Assuming 100% efficiency (which never happens), the EFFECTIVE speed is 50mbps since the wireless AP can only communicate w/ one or the other desktop at a time. That’s something ppl don’t always take into account.

"Superfetch" and "Remote Differential Compression" sound like classic examples of MS being almost too smart for its own good. Like most such “features”, MS is always going to enable them by default lest no one use them. There are lots of other features/services you don’t need in Windows either, but MS enables them by default otherwise they would not be used (only experts would even know they exist). In the MS world, the philosophy is “better to enable features that may never be used, than disable features and guarantee it”. On the downside, it may be raise problems in other areas.
February 21, 2010 3:49:14 PM

Hi eibgrad,

Thanks for the reply. I have checked everything on the network sides etc, and they are all connecting at 1000 Full which is fine. So basically I have a new Linksys WAG ADSL2+ Router with 802.11n specs connected via 1000mbps into the NETGEAR Switch. This Linksys Router provides my Wi-Fi N Access and generally it would only be my Laptop connected doing the main transfers at any one time.

If I am connected at over 200mbps which I always am, and usually around the 300mbps mark, it shouldn't be unreasonable to expect better than 10MB/s performance which I never seem to get out of the wireless??

So that aside we return to the Gigabit Ethernet directly connected over quality CAT 5e at less than 2m long each, between the individual devices say Desktop WIN7, NETGEAR Stora NAS, and NETGEAR Gigabit Ethernet Switch. Surely it shouldn't be unreasonable to expect 50-75MB/s performance on this???

The Gigabit Ethernet can easily handle it, the Velociraptor 10k SATA II drives can handle it, so too can the P5B Deluxe Board, yet we see a CAP at 21.5MB/s???
Only after Superfetch and RDC was disabled mind you - I can't believe MS would implement something like this by default!!?

I am an ICT professional for over 12 years now originally working with systems and servers etc, but now with Networks etc, I can't believe that this is such a common issue. I looked on forums on the net and the amount of people having issues like this is crazy, and I can assure you I never ever heard of "Superfetch" or "RDC" before. It took a very long time over at MS Forums before someone suggested doing the above, this why I am worried there may be more default WIN7 "Services and Features" which might need to be disabled to push the performance above the 21.5MB/s bottleneck I seem to be at at the moment!?!?

I know there is a feature in TCP/IP called "Global Synchronisation" which can cause bandwidth to go up and down and then restart all over again when it trys to take too much data in etc, since the network will try get as much data as it can until it overflows etc. However, when I view the MS Performance Monitor I can see this phenomena happening as expected on the NIC (from the Greeen Graph), but the problem here is that the CAP of the Data always seems to be "Hard-Lined" at around the 20% Mark which would co-incide with the 21.5MB/s bottleneck I am seeing on this Network!!?

So we all agree and accept that we are NOT going to get 100% efficiency on any of the Networks we use, be it Wireless or Wired, however 5, 10, 15, 20 and 25% efficiency seem a far way off from an acceptable level of transfer rates, especially given todays hardware and software advancements etc.

If the answer lies with Superfetch, RDC and other "Obscure" MS technologies, then I would very much appreciate any extra information anyone may have on these "Services" etc.

Gone is the day when we could just plug a computer into a network and get the rates we were meant too!!!!??

Thanks,
Ian.
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February 26, 2010 2:31:17 PM

If this is considered a "hijack" of this thread let me know and I'll go elsewhere. But the two of you sound like you would be able to answer my question.

The problems discussed here seem to touch on my experience when backing up my laptop to a desktop.

I'm running Win 7 and both systems have adequate performance. Let me know if you need more detailed specs. Initially I'm looking more for a "sounds like you have a big problem" or "14 hrs sounds about right" type of answer. If I have a big problem then I'll dig in and do more research, but like ianjf, I often find it difficult to find answers and sometimes you just need some help to ask the right question.

I first attempted a back up over my Wireless g network. The two systems were the only ones active at the time. After several hours I cancelled the back up since progress appeared very slow.

I then connected the systems using a crossover cable (the adapters are 10/100) thinking that a direct connection would be faster. The backup took about 14 hours for 100 GB of files. This was the first back up and I let Windows 7 set the parameters and I believe a system restore point was created. I have not attempted another back up.

Can either of you enlighten me as to whether a 100GB back up should take this long? Should the time be similar or vastly different between wireless and direct?

I would prefer to back up using the wireless. How should the speed of the wireless connection compare to the speed of the direct connection?
February 26, 2010 3:03:59 PM

BlueCat57 said:
If this is considered a "hijack" of this thread let me know and I'll go elsewhere. But the two of you sound like you would be able to answer my question.

The problems discussed here seem to touch on my experience when backing up my laptop to a desktop.

I'm running Win 7 and both systems have adequate performance. Let me know if you need more detailed specs. Initially I'm looking more for a "sounds like you have a big problem" or "14 hrs sounds about right" type of answer. If I have a big problem then I'll dig in and do more research, but like ianjf, I often find it difficult to find answers and sometimes you just need some help to ask the right question.

I first attempted a back up over my Wireless g network. The two systems were the only ones active at the time. After several hours I cancelled the back up since progress appeared very slow.

I then connected the systems using a crossover cable (the adapters are 10/100) thinking that a direct connection would be faster. The backup took about 14 hours for 100 GB of files. This was the first back up and I let Windows 7 set the parameters and I believe a system restore point was created. I have not attempted another back up.

Can either of you enlighten me as to whether a 100GB back up should take this long? Should the time be similar or vastly different between wireless and direct?

I would prefer to back up using the wireless. How should the speed of the wireless connection compare to the speed of the direct connection?


Let’s run the numbers…

100GB = 100,000MB = 800,000mb

Let's assume about 70% efficiency over 100mbps wire:

800,000mb / 70mbps = 11429 secs, or 3.17 hrs

Let’s see what wireless can do. Let’s assume wireless G, maybe 22mbps (perhaps a bit optimistic, but let’s assume the best):

800,000mb / 22mbps = 36363 secs, or 10.1 hrs

You were getting 14 hrs, let’s calculate the wireless speed:

14 hrs = 50400 secs

800,000mb / 50400 secs = 15.87mbps (hmm, sounds plausible)

Of course Gigabit would be ideal (again, let’s assume 70% efficiency):

800,000mb / 700mbps = 1143 secs, or 19 mins! :D 

As far as wireless, 14hrs seems plausible for G (I’ve seen worse and better G performance, you seem to be a bit on the lower end of the spectrum than most). Obviously wireless N would produce better results than G.
February 26, 2010 4:45:36 PM

check out a similar post I just had.. I kind of solved it myself

http://www.tomshardware.com/forum/28623-42-weird-networ...

this may not work for you, but it's worth a try. My second post is the one with the answer.

You have to restart after changing auto-tuning.

I went from ~1MB/sec to 110MB/sec on Windows file sharing

I'm not even sure how superfetch would affect your network performance. disabling it should make your system seem a bit slower in general though.
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