Icon: Drek's HLDS / SRCDS rate calculator Drek's HLDS / SRCDS rate calculator

This handy little chappy will calculate the recommended number of slots your HLDS or SRCDS server can run with rates, as recommended by Drek.

All calculations are directly from Drek's guidelines "setting rates for small home servers" (formerly "running a lag free server"), but since nobody can be bothered to read his highly useful and well structured advice, I have built this.

This script should work in IE/Opera/Firefox now. Thanks to pizzahut for help on getting it to work in Firefox.

20/Nov/2016: Increased GoldSrc maximum rate to 100,000 (SteamPipe) and added Sven Co-op dedicated server.

Rates calculator (20/Nov/16)
Game server engine Throughput
HLDS: GoldSrc games
SvenDS: Sven Co-op version 5.0+
SRCDS: Source games
Enter your upload speed or download speed, whichever is smaller:

% of your throughput will be unused, so will be used.
Not sure? Take a speed test.
Hardware allocation Recommendation Notices
MHz CPU with executable thread(s)
of primary memory
0 slots(s) max recommended
Running slots(s), including reserved

sv_minrate 0
sv_maxrate 0
sv_minupdaterate 0
sv_maxupdaterate 0
Still experiencing bad lag after using the recommended settings?
If you are still having problems with unusually high or unstable pings, lower your sv_maxupdaterate one at a time until your pings are stable and as low as they are going to be. You shouldn't have to lower it any further than half the number I gave above.

If your pings are low and stable with a full server, try raising your sv_maxupdaterate one at a time until your pings go wonky, then lower it back to the last good number.

Not got a clue what to enter? Here's some help.

Game server engine

Select the game engine your servers will be running.

Throughput (wrongly aka bandwidth)

Simply the lowest amount of throughput you have available to the Internet. If your downstream speed is 4 megabits, and your upstream speed is 512 kilobits, enter 512.

If you honestly have no idea, try the speed test. Do 2 or 3 tests on the recommended testing server to get an accurate result, then take the lowest figure out of downstream/upstream and enter it in the box.

5% of the value you give us will be taken off mainly to leave a gap that may be required for other protocols.

Finally, I call this throughput rather than bandwidth because bandwidth is a term used in radio frequencies. As computer scientists we should be using the correct term throughput to determine the amount of data we can put through a logical link within a certain time lapse.


We now need to know details about the server computer.

Once you enter your server processor speed, number of processors/cores, and total primary memory, the script will recommend how many slots it can handle.

Either take the recommended slots and type it in the player(s) including reserved slots box, or type in your own figure.

If you are recommended more than 32 slots, don't worry -- it isn't broken. This means you can run multiple servers up to the player count shown. For example if you are told 50 players, you could run 2 servers at 25 players each, or you could run 3 servers at 20/20/10 players.

Ensure you enter the total slots across ALL servers you intend to run on the machine. If you will be running 2 game servers with 20 slots each, enter 40. If you were to put in just 20, the rates advised will be for just 1 of your game servers.


Once you've filled in the throughput and players, you can calculate the rates recommended for your server configuration file. Simply copy and paste the results in to your server.cfg file.

If you would prefer to have an application for Windows that does this, see my original creation of this tool.

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