Firstly, for those like me, the Core i7 is the newest cpu from Intel.  The chip has four cores and two process threads each, so you can run

eight concurrent programs without a hitch.  The truly amazing part of this cpu though is the overclockability.  I bought the Core i7 920 which is clocked at 2.6Ghz by default.  After toying around for 6+ hours tweaking this and that I ended up stable at 4Ghz.

The cpu is very stable and sturdy, even at almost 1.7v core (default 1.25).  Compared to my old FX-55 ( remember how leet that processor used to be, haha ) its like a different world.  As you can see from the picture I am currently running at 3.6Ghz because the processor was getting a little to hot when under load.  It would peak at 90 degrees celcius at 4Ghz, max operating tempurature is widely accepted as 100 degrees celcius.  This is not documented or set by Intel, its more of a rumor.  Apparently at 100 degrees the cpu starts to underclock itself, therefore 100 degrees is the max.

Also, unless you are very lucky in order to achieve 4Ghz you must enable Intel’s Turbo Boost technology, which automatically adjusts the cpu multiplier based on load.  Usually the cpu’s multiplier is set to 20, but with Turbo enabled and heavy load the cpu will overclock to 21.  Unfortunently according to the posts I read online when the cpu overclocks itself it only overclocks a couple of cores.  Therefore even though the cpu makes it to 4Ghz when under load its really just a number, the true frequency is a bit lower.

Therefore I decided to disable Turbo and leave the cpu at 3.8Ghz for a time.  After a few days I decided to lower it further to 3.6Ghz to keep the voltage within spec.  Believe me though, the Core i7 is an amazingly strong overclocker.

As a special note, the board I got does not allow setting the multiplier over 20, but I hear talk of a future bios update to allow it.

First off, I should explain that I wrote a plugin for Team Fortress 2 called TFTrue. This plugin maintains critical chance and damage for server owners wishing to change the default settings. To make the plugin I had to study the take damage function in the game to figure out where the percentages were coming from ( which if you are curious, default you have a 5% chance to crit with weapons and 15% chance to crit with melee ). I thought this statement was weird because after all my searching I never came up with any ‘skill’ variable that increased or decreased the crit chance. I setup my test to work out all the unknown variables in the game code and find out whether or not score has an impact on your crit chance. I will summarize my data here, if you want to refer to the hard data, see the end of this article.

I setup a private server with TFTrue installed and crit chance set to 50%. I made a test map with 1 spawn point and set the respawn time to 0. This made my bots all spawn in the same place with little death delay. I expended 80 rounds of rocket ammo at a wall and observed my critical count. For my control test I ended up with exactly 50% critical chance, so far so good. Next I stepped it up, introducing 7 bots on the opposing team to test the idea that being out numbered helps. After firing all 80 rounds, my crit chance still remained 50%.

Next test involved killing the bots enough to achieve the ‘domination’ status with all of them. With my high score and high skill (according to the game), I fired 80 more rounds at the wall. Still 50% crit chance. What does this mean? It means being consistently better than the other players will not increase your crit chance.

The final test I did was tacked on as a side note when I noticed something interesting while killing the bots. It appeared that I was getting all crits when constantly killing the bots as they spawned right in front of me. So on a hunch I started firing constantly into the crowd of bots and low and behold, 100% crits for all 80 rounds. Upon further investigation I found that after killing 2 players in quick succession increased your crit chance about 4 times. Meaning default crit chance would become 20%. This effect lasted a variable amount of time depending on the weapon type. I timed the demoman’s sticky grenades to last for a bout 20 seconds, however the rockets only lasted about 5. To figure out what specifically influences this behavior we must look back at our code.

Before the Nov. 7th patch, Valve had kept private critical chance variables in the game. Namely, tf_crit_chance, tf_rapid_crit_chance, tf_melee_crit_chance. The first and last variable are pretty much self explanatory, however, what is rapid crit chance I wondered. Back then I decided that it was the chance to crit while firing rapidly. However after reviewing my test results I now believe that maybe this rapid chance is what determines critical chance when killing players rapidly. This is all theory and I have not tested it, but I do think that while playing if you kill a player the game rolls a number to compare to the rapid chance and turns crits on for you if you are lucky. After the Nov. 7 patch the TFTrue plugin treats both those numbers the same, they are both controlled by tftrue_crit_chance. And after further reviewing the code it supports this idea. So if we do work with this theory lets walk through a typical game.

Player Spawns
Player Shoots gun at wall (5% chance to crit)
Player runs to enemy territory
Player kills enemy player (5% chance to start “crit chain,” if the player if lucky he will now shoot crits for X seconds)
Player kills another enemy (5% chance to start “crit chain,” regardless if they are in one or not)
Player shoots (5% crit chance, unless in crit chain, then its 20%)
Player Dies.

I think if you are a hard core tf2 player you can easily identify with this result, just remember that this senerio is purely hypothetical. I have not done any tests modifying rapid crit chance. Like I said earlier however, the code supports this situation.

Now we must turn back to our original hypothesis. Does the critical hit chance get bigger the better you do? In one word, no. However I think we can easily see how Valve would mix up this system with a skill reward. In this system you can be a complete noob and get 1 kill to put you in a crit chain. Your skill as a player has no bearing on the crit chance. How you get more crits in tf2 is to kill more people. The more people you kill, the more shots you have at hitting that 5% chance on the nose.

Test Data:

Test 1: 15 / 40 crits | 24 / 40 crits
Test 2: 18 / 40 crits | 20 / 40 crits
Test 3: 22 / 40 crits | 18 / 40 crits
Test4: 39 / 40 crits | 40 / 40 crits