Hi,

I was in doubt if post this or not because I couldn't replicate with enough similarities. But as it may be worth, if it is an actual bug, or help others... why not?

Here I have to say that it is more noticeable under Windows 2000. That doesn’t mean doesn’t happen on higher OSs, but, from XP, it isn’t as noticeable. So, please, don’t stop reading here. But, hey, I know it is obsolete, and I know this is long and I’ll understand if you don’t want to read this.

I tend to make a lot of “speed tests” because ISPs in my country… well, if you have luck, great, if not, brace yourself with the fights. Maybe as other countries :/

About February my download broadband was enhanced from 30Mb to 50Mb. This is important because is when it started all. With only 30Mb I didn’t notice any problem.

“Speed tests“ were fine with “only” 30Mb and all matched the contracted speed and even a bit more. But when I had 50Mb I started to see some annoyances that sometimes was over 50Mb and others... if I had the luck to have 30Mb, it was a miracle. It wasn’t the test used. It was any test, with any technology (flash, html5, java, etc). The difference was just a couple of Mb. But all reflected the problems.

They were so random, but something in common is that the tests didn’t show the correct speed at the end of my PC usage day. So I thought, something in memory, maybe, was causing it. But, also, it didn’t happen all days. At the end of the day, sometimes, I topped the 50Mb.

And here starts the discarding process.

I have a humble Pentium 4 and, even it is not powerful, one of the things I do (that I won’t explain why) is to throttle it (decrease speed). It is one of the first things I discarded, because as higher the broadband, the CPU load at full speed is higher as well. I only noticed a little improvement. This wasn’t the problem. Even I uninstalled the filter driver.

So, if the CPU wasn’t the problem, programs should be. And I started with everything. And I left Stunnel as one of the latest. And there was the problem.

When Stunnel is open, the speed cuts at about 30Mb. Yeah, I couldn’t believe myself either.

After several tests, I discovered that Stunnel isn’t either the problem itself. The problem comes from the amount of services in .conf file. The more you have, the more speed problems you’ll have. I discovered this with the second instance of Stunnel I use for servers, which only has 7 services (3 SNI).

I mainly use Stunnel as client for non-SSL aware programs and I have set 16 services. The options of .conf file, or services options, seems to don’t have much effect on speed tests.

At the end, one way or another, the result is that if I open Stunnel, I can’t top full speed. I close it and voilà!, even during the same speed test.

What is causing it? Probably just Windows 2000, or maybe not. Windows 2000 doesn’t have a connection limit as XP, one of the things I thought about. Anyway, I just wanted to shared this with you, just in case helps or anything.

Regards.

System specifications: Windows 2000 SP4 // XP SP2 (testing purposes) P4 2.8Ghz RAM 2GB RTL8139 Fast Ethernet Full Duplex