Garmin plunged 5.3% after the stock was downgraded by a Wall Street firm over fears of increased competition, slowing growth in Europe and margin declines. A Deutsche Securities analyst downgraded the stock to hold from buy and reduced its price target to $90 from $125. Shares were down $4.21 to $75.99. AMD ( AMD) continued to decline, falling 7.8% after two Wall Street analysts expressed concerns about growth in the semiconductor market. An analyst at American Technology Research reduced the rating on eight chip stocks on the belief that the bookings outlook for first quarter 2008 is weak. The analyst also lowered fourth-quarter EPS estimates on AMD ahead of the company's Jan. 17 report. The stock was off 47 cents to $5.53. Spectrum Control ( SPEC) got clocked, losing 31% to $9.76 on a disappointing fourth quarter. The Fairview, Pa.-based maker of electronic control products posted income of $3.2 million, or 23 cents a share, vs. $2 million, or 15 cents a share in the year-ago quarter. The results fell short of one analyst's expectation for EPS of 25 cents, per Thomson Financial. Meanwhile, shares of Perficient ( PRFT) lifted 14.5% to $17.00 on raised guidance. The Austin, Texas-based provider of e-business solutions raised its fourth-quarter revenue expectations to between $61.2 million and $62.7 million, up from a previous range of $56.3 million to $62.1 million. The average analyst expectation is for revenue of $60 million.