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23. What do I choose in the "Connection Speed" slider ?

You should pick your maximum available downstream speed, as advertised by your ISP.

The "Connection Speed" slider displays speed in Kbps (kilobits per second). To convert from Mbps, or any other units of measure, feel free to use our Bits/Bytes Conversion calculator.

For example, 7 Mbps connection equals 7000 Kbps.

Note: Even though the current version slider only goes up to 20 Mbps, the values for 20 Mbps work well for connections up to about 35 Mbps as well. For even faster connections, note you have to actually be able to achieve near 100% of your maximum throughput in order to see any speed difference from higher buffers.

  User Reviews/Comments:
by anonymous - 2006-04-13 02:20
could you please add from FAQ this info or link to 'how to determine your connection speed' to the general instructions >2. Using the Program>choose your maxium connection speed
by montrose9272 - 2006-05-24 00:54
The slider only goes up to 20000.
My ISP (Optimum) is advertising that the Boost feature I purchases is up to 30 Mbps. What do I do to set the slider higher, or will this be included in the next version of the Optimizer?
by Philip - 2006-05-24 19:20
Please post questions to our forums. The "connection speed" slider in the Optimizer only goes to 20 MBps, however the same values work well with up to 30 MBps as well.
by CJames - 2007-02-12 14:10
Where do ya put the slider if your are linked to a wi-fi connection and not sure of the downstream time?
by techjunky - 2008-03-13 10:26
Why has the slider been set to a max of 20mbit?

Will this affect the speed in which my other LAN devices communicate internally? They operate at 100/1000mbit so can I expect a drastic decline with internal bandwidth should I run this on my adapter?

Even for an external connection, if I was sat on a 100/1000mbit external server, regardless of overheads etc, in theory, this utility would seriously cripple the bandwidth.

Please could someone let me know before I go ahead and use this. Thank you :)
by Philip - 2008-03-13 15:44
The TCP Optimizer increases buffers from the Windows default values, so, if anything, it will only have positive effect on your LAN connection as well.

LAN traffic has much lower latency, and therefore works well even with the Windows default lower buffers. Increasing the buffers has the potential of improving all TCP/IP transfers, but it is more noticeable on the WAN side.

The "20 Mbit" slider bar option in the Optimizer is intended for a 20 Mbit WAN connection. It would work well even with a gigabit LAN connection because of the negligible latency.
by anonymous - 2008-03-17 16:06
Not working for me! I save them, reboot, and nothing happens, still the same 1600 kbs on speedtest for me, I have a 100 mbps local area connection!
by Philip - 2008-03-17 16:36
The local connection is not the limiting factor in internet speed testing.
by anonymous - 2008-12-11 17:11
I have a 110 Mbps WAN connection. My avg download is 95000 kb/s. Should I use optimizer (Slider goes only up to 20Mbs)?
by Philip - 2008-12-12 11:47
The default TCP Window is VERY low, so using the Optimizer will help your internet connection even if your exact speed is not in the slider bar.

For connections higher than 40Mbps, you should start with the slider at the highest setting (20Mbps), and if you're feeling even more adventurous, you can use the "Custom" mode to double the number in the "TCP Receive Window".
by anonymous - 2008-12-14 08:49
reference: anonymous 2008.12.11 17:11

It really works - thanks!

New max results: download 114533 kb/s upload 4633 kb/s / recommend server
(Slider:20000, Optimal, TCP Receive Window 1027840)
HPCompaq_nx7300 T5600 @ 1,83 GHz
Firefox 3.04
CAT6 cabling (Delta SuPremeNet 250 FTP Gigabit)
HP ProCurve Switch 1400-8G
Cisco ASA 5505 Firewall
Cisco EPC3000 Cable modem
by karmpf - 2009-07-12 17:41
Im using 100Mbps local area connection... What setting should I use to make this work, coz I already tried it and set it to the highest 20000Kbps and reboot it and nothing happened...still the same speed test..and ping..please help im a beginner and not much of a computer genius..thanks.

P.S. I just wanted to remove the lagging when I watch HD movies online

by Philip - 2009-07-14 04:55
Note that the Optimzer can only tweak your end of the connection. If you already applied the optimal settings the bottleneck is no longer your computer, but the line is still limited and dependent on your ISP, the quality of the line they provide.

I hope this helps, you can try our forums for more specific tweaking details.
by anonymous - 2009-09-28 19:58
My ISP says that my internet connection speed is 6Mbps down and 2 Mbps up. Which number should I use in optimizing my connection?
by Philip - 2009-09-29 08:51
You should always choose your advertised downstream speed.
by duke52 - 2009-11-18 15:17
I've tried TCP Optimizer and it's not working for me! I save them, reboot, and nothing happens, still the same 1000 kbs on speedtest for me, I should be getting over 7000 kbs. Any ideas?
by anonymous - 2010-03-03 16:43
I've just installed a 50 megabit modem. And yes, I do get pretty close to that theoretical speed - on downloads, at least. However, some Web pages actually seem less responsive than before. Hence my interest in your tweaks.

The question is: I've applied your tweaks using the max 20000 Kbps setting. Is this going to do the trick, or would Web surfing benefit from even higher settings? (For example, a larger RWIN...)
by Philip - 2010-03-05 09:53
Yes, the 20Mbps speed slider setting will work well for a 50Mbps connection.

You'd only need a higher RWIN setting if there is excessive lag on the line to a particular server, i.e. > 300ms.
by heiny - 2010-07-09 02:05
hi, i just muvd d slider & chose custom settings. after applying it gives error msg: Element not found. please help
by Philip - 2010-07-09 15:09
Please use our forums for questions about the Optimizer:
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