The TV show is (paradoxically?) more vulgar but also more good-natured (being a comedy) than the real thing.
For example, no one would call a VC a "choad-gargling fuck toilet" in a pitch-- VCs share notes more than is appropriate or legal, and have black-balled people for less-- and I doubt that a group of typical startup engineers could pull off a flawless 3-minute dick joke like the one in Season 1's finale. So, the TV version of the Valley is more overtly vulgar. The real thing tends to be crass and exclusionary, but you're not going to hear words like "shit-riddled anal wasteland" or nicknames like "Cunty" very often. The show focuses on superficial abuses that are funny rather than the long-lived, subtle, and often subversive ones that characterize the actual Valley.
Another discrepancy: when Richard achieves a record-breaking "Weissman score", the entirety of TechCrunch disrupt is in awe. In the real Valley, 95% of them wouldn't know what a Weissman Score is. The technical literacy of the people in the show is actually much higher than in the real Silicon Valley. At one point, there's a reference to a "DFT" (Discrete Fourier Transform, I presume) and I'd bet that only 1% of investors and 5% of SV founders know what a Fourier Transform even is.
The show gets far more right than I would have expected, and more right than it gets wrong. One of the things that is true to life is the purely political promotion of Bighead (an incompetent engineer who gets a great job because the CEO of Hooli wants to fuck over Pied Piper). That happens a lot and I'd love to see his career grow and for him to become a VP, a founder, or even get promoted into the investor ranks. The part that isn't true to life (or, at least, very common) is his humility and self-awareness. He knows that he's mediocre; whereas most people who benefit from political or aggressively aspirational promotions tend to believe they actually deserved it, and get quite arrogant.
Another thing that's true to life is Russ Hanneman's unethical use of information, when he poaches an engineer that Pied Piper wants for another company. That may be the core ethical flaw of Silicon Valley: a complete lack of respect for the idea that there are things that one should not do with others' information. That sort of ethical looseness is common and spot-on. Likewise, the herd mentality of the VCs around Pied Piper hits reality exactly.
Finally, you have Erlich Bachmann and Russ Hanneman (inspired by Sean Parker and, some have said, Mark Cuban). Bachmann is a jerk, superficially, but still a bit too good-natured to be a real player, as we've seen in the recent episodes. Russ Hanneman hits the archetype of the Silicon Valley billionaire ("three comma") on the nose. That said, even he's more self aware than most real SV billionaires.
I was also surprised by that when watching the show, but I believe it was Gavin Belson who hyped this metric while presenting Nucleus at Tech Crunch. Most non technical people would have understood the Weissman score as "something that measures how good a compression is, the higher the better, and since G.B says 2.98 [or something] is record breaking, it must be the case.", so when Richard achieved a Weissman score of 5+, the same non technical people concluded that an algorithm with a score of 5+ must be totally revolutionary.