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On my wifi router i have set the mode to 150Mbps, but when i connect to this router it shows only 65 Mbps on my laptop. Why it is so? Does that mean my router is not capable to transfer at 150Mbps or my laptop is not capable to receive at 150Mbps?

Laptop: Lenovo y470 ( core i7 ) [OS: Win 7]
Router: Netgear N150

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Note it says "Up to 150 Mbps". –  techie007 Nov 19 '11 at 15:11
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@techie007 does that mean my router is not capable of transferring at 150 Mbps –  Rakesh Juyal Nov 19 '11 at 15:43
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There are so many factors that could cause a speed decrease, and many of those are environmental (ie: a microwave, a wall, a nearby nuclear power plant, etc.), which we can't speculate on. Just keep in mind the connection is trying to remain 'stable', not 'fast', and it could be either end making these types of adjustments. –  techie007 Nov 19 '11 at 16:57
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3 Answers

up vote 9 down vote accepted

Short answer: That's the best your card can do when communicating with your AP.

Long answer:

Lenovo says your Y470 contains an "Intel 1000 BGN Wireless" card. Apparently it's more properly known as an "Intel WiFi Link 1000 BGN" card.

According to the Wi-Fi Alliance's certificate for that card, it is only capable of a single transmit stream (that is, it's not actually MIMO on transmit), and it is not capable of HT40 (a.k.a. "wide", 40MHz channels). In effect, it's pretty much "N in name only". The best speed it can transmit at it 65 or maybe 72.2 megabits per second.

Your card looks like it's capable of receiving 2 spacial streams at HT20, which means that with 2- and 3-spacial stream N APs (Wi-Fi routers) it could receive at up to 144.4 mbps, but unfortunately your AP is another form of non-MIMO -- and thus basically "N in name only" -- AP. It only supports a single spacial stream, although it does support 40MHz channels. So the best signaling scheme your AP and client both support is single stream HT20, which tops out at 65 mbps with a long guard interval, or 72.2 mbps with a short guard interval.

The Wikipedia article on 802.11n has a nice table of 802.11n data rates based on the number of spacial streams, 20- or 40MHz wide channels, and long or short guard intervals.

It's sad to me that so many "N in name only" products are being sold that don't really support the flavors of N that make it shine. The 65mbps that your card/AP combination tops out at isn't that much better than the 54mbps that 802.11a delivered a decade ago.

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what the ... that means LENOVO cheated me. That's not good. –  Rakesh Juyal Nov 26 '11 at 12:12
    
@Rakesh: No, it means that Netgear misled you. The wireless card in the Lenovo should work fine with an AP that supports MIMO. –  cmorse Jan 5 '12 at 5:52
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@cmorse Only in one direction. I feel like both his AP and his card are ripoffs, since the first-generation N gear all did 2x2:2 HT40 in both directions, establishing N as a 300mbps technology. Anything that calls itself N but isn't as fast as the oldest draft-N gear was (from way back in late 2006, no less) is kind of a ripoff. I think most people expect newer-generation products to get better, not worse. –  Spiff Jan 5 '12 at 7:09
    
@Spiff I didn't notice that the MIMO was only supported on transmit. I agree with you then, the card is a ripoff. –  cmorse Jan 6 '12 at 15:26
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Most 802.11n products will knock your throughput down by up to 80% if you use WEP or WPA/TKIP security. The reason is that the 802.11n spec states that the high throughput rates (link rates above 54 Mbps) can't be enabled if either of those outdated security methods are used.

Quoted from 5 Ways To Fix Slow 802.11n Speed on Small Net Builder

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This quote is sort of false. if you enable WPA+AES WPA2+AES then your throughput is not decreased. I have to downvote this answer for half of the information. NO WIRELESS shoudl be used without somee sort of encryption. –  Ramhound Jul 25 '12 at 20:29
    
1. This question is 8 months old. 2. My answer says what your comment says. If outdated, non-WPA/2+AES, encryption is used, data rates are slower. The implication bring the best encryption will allow better data rates. –  Ampersand Jul 26 '12 at 13:45
    
I blame the system that makes 8 month old threads, that don't actually need to be brought to our attention, but I still say the quote is incomplete. If you use WPA+AES your throughput is not not affected. –  Ramhound Aug 1 '12 at 11:23
    
@Ramhound I agree that it could have been explicitly stated. –  Ampersand Aug 1 '12 at 16:27
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Actually I have noticed that Windows 7 limits channel bandwidth to 65mbps. I have a netbook that gets 65 even next to the router and the PC only gets 130 (dual channel wi-fi). Both are running W7. The PC used to run Vista and got 300. We have a laptop that is running XP and that gets 150 (single channel).

I've noted a lot of very similar posts all Windows 7 and all complaining at a 65 top speed. Some have noted that dual-booted machines get correct speeds on alternative OS but for some reason no one has yet realised the issue is with Windows.

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This has nothing to do with Windows 7. –  Ramhound Jul 25 '12 at 20:31
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protected by harrymc Jul 25 '12 at 21:00

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