Fastest API for rendering text in Windows Forms?

Question

We need to optimize the text rendering for a C# Windows Forms application displaying a large number of small strings in an irregular grid. At any time there can be well over 5000 cells visible that update 4 times per second. The font family and size is consistent across the cells, though the color may vary from cell to cell, as will bold/italic/plain.

I've seen conflicting information on the web about TextRenderer.DrawText vs. Graphics.DrawString being the fastest/best, which reduces to a GDI vs. GDI+ comparison at the Win32 level.

I've also seen radically different results on Windows XP vs. Windows Vista, but my main target is Windows XP. Articles promising great advances under WinFX and DirectX 10 aren't helpful here :-)

What's the best approach here? I'm not afraid of introducing a small C++/CLI layer and optimizing device context handling to squeeze out more performance, but I'd like some definitive advice about which direction to take.

EDIT: Thanks for the initial responses. I'll be trying a combination of background bitmap rendering and sticking with the GDI equivalent calls.